Vocabulary for Biology/HSB/Integrated Science Copyright: Benedict Institute of Learning

1. Absorption: a process that takes place mainly in the small intestines. Food particles that are small enough (such as glucose,
amino acids, water, vitamins and minerals) can pass through the intestinal wall and into the blood stream.
2. Accommodation: When the lens of the eye adjust to seeing father and nearer.
3. Acetylcholine: a neurotransmitter that reduces heart and respiratory rates; increases skeletal muscle contractions.
4. Acrosome: located at the cap of the sperm’s head. Contains enzymes to penetrate into the egg.
5. Active transport: molecules moving from a lower to higher concentration using ATP (energy).
6. Active immunity: producing antibodies by fighting an infection.
7. Adrenal glands: located at the top of the kidneys; produce the hormone, adrenaline that increases heart and respiratory
rate; reduces salivary secretions, peristalsis and urinary bladder contractions.
8. Aerobic respiration: metabolism that uses oxygen, also referred to as cellular respiration. Glucose + Oxygen  Carbon
dioxide + Water + Heat + ATP
9. Aedes Aegypti: mosquito that carries the dengue virus
10. AIDS: Acquired Immune Deficiency Syndrome. The immune system is very weak and cannot fight off pathogens. This causes
death from a variety of infections, including fungal, bacterial and viral. A person with AIDS also cannot fight cancer.
11. Alveoli: air sacs in the lungs with elastic walls that inflate and deflate to allow inspiration and expiration, respectively.
12. Amino acids: the building blocks of proteins.
13. Amniotic sac: the membrane surrounding the fetus containing amniotic fluid that absorbs shock.
14. Amylase: a digestive enzyme found in saliva and the small intestines. Amylase breaks down starch into maltose.
15. Anemia: an illness due to a low number of red blood cells. This can be due to a lack of iron in the diet. Symptoms include
fatigue and paleness of the skin.
16. Anaerobic respiration: metabolism of sugar that does not involve oxygen. This is the principle means of glucose metabolism
in bacteria. (Note: animal cells also perform anaerobic respiration; but it is followed by aerobic respiration)
17. Antibiotic: medication used to kill bacteria.
18. Antibody: a protein produced by plasma-cells of the immune system that targets specific antigens (pathogens).
19. Aorta: largest artery in the body that carries oxygenated blood out of the left ventricle of the heart.
20. Arteriosclerosis: a non-infectious disease characterized by hardening of the arterial walls. This can generally result in
hypertension (high blood pressure) and eventually rupturing of the wall (bleeding).
21. Artery: a blood vessel that carries blood away from the heart; the blood pressure is high; arteries have elastic walls; in most
cases, the blood is oxygenated.
22. Artificial immunity: when the immune system produces antibodies due to exposure from a vaccination.
23. Asexual reproduction: only one parent involved; process is generally quick; genetic variation is low.
24. Asthma: a non-infectious disease characterized by increased mucus and inflammation in the airways; smooth muscles
around the bronchioles contract to cause closure of the airway. This is due to a trigger, such as animal hair, dust or pollen
grains.
25. Atherosclerosis: a non-infectious disease characterized by the build-up of plaque in the arteries due to a diet high in bad
cholesterol. This blocks blood flow, resulting in oxygen deprivation to the cells in that area.
26. Axon: elongated segment of a neuron that releases neurotransmitters into the synapse.
27. Ball and socket joint: a freely movable joint such as the shoulder joint and hip joint.
28. Benedict’s reagent: a blue reagent that turns orange when mixed and heated with a reducing sugar such as glucose,
fructose, galactose, lactose or maltose.
29. Beriberi: a thiamine (vitamin B1) deficiency that causes swollen legs and digestive problems.
30. Bicuspid valve (mitral valve): prevents the backflow of blood into the left atrium.
31. Bile: digestive juice produced by the liver that emulsifies fats (increases surface area of fat for digestion by enzymes to be
faster).
32. Binary fission: a form of asexual reproduction performed by bacteria.
33. Bowman’s capsule: the beginning of a nephron where the filtered components of the blood are collected. Large proteins
and blood cells cannot enter Bowman’s capsule.
34. Capillary: the smallest and most fragile blood vessels; walls are only one cell thick; exchange of gases.
35. Carbohydrates: macromolecules (food) that provides energy.
36. Carcinogens: a chemical that causes cancer.
37. Carnivore: an animal that eats only meat.
38. Cartilage: a type of connective tissue located in various parts of the body: nose, ears, rings of trachea and ribs.
39. Catalyst: another word for an enzyme. Catalysts speed up reactions by reducing the activation energy.
40. Cellulose: a complex sugar found in the cell walls of plant cells. It cannot be digested and is therefore the insoluble fiber
(roughage) that cleans out the digestive tract.
41. Central nervous system: brain and spinal cord
42. Cerebellum: controls involuntary movements. For example, keeping your neck upright; staying balanced when touching
your toes.
43. Cerebrum: contains the four lobes – frontal, temporal, parietal and occipital.
44. Chloroplast: organelles in plants cells that perform photosynthesis.
45. Cholera: caused by drinking water with sewage (feces). Symptoms include diarrhea, vomiting and fever.
46. Chromosome: contains genes (DNA). Two chromatids make a chromosome.
47. Ciliary muscles (body): muscles that pull on the suspensory ligaments to stretch out the lens to see objects far away.
48. Conditioned reflex (reflex action): a response that does not involve the brain. Eg. Pulling away one’s hand from a hot stove.
49. Cones: cells in the retina that detect color (day light).
50. Continuous variation: a trait that varies in degree; for example, skin color and height.
51. Contraceptive pill: contains estrogen and progesterone that prevents ovulation from occurring.
52. Cornea: front lens that bends the light as it enters the eye.
53. Corpus luteum: a scarred follicle that produces estrogen and progesterone to keep the endometrium thick.
54. Cowper’s gland: located at the base of the penis; keeps the urethra lubricated and regulates its pH; also lubricates the tip of
the penis.
55. Crossing over: occurs during prophase I of meiosis I. Homologous chromosomes exchange genes to increase genetic
variation of the offspring.
56. Cytoplasm: jelly-like substance in a cell in which the organelles float.
57. Dark reaction: also called the light-independent reactions because sunlight is not necessary; during this time, the Calvin-
Benson cycle in the stroma of the chloroplast produces glucose from carbon dioxide.
58. Dendrites: projections of a neuron that receive neurotransmitters.
59. Dengue hemorrhagic fever: an advanced stage of dengue that involves severe bleeding from the nose and underneath the
skin. Blood transfusions are implemented to treat this stage.
60. Dentine: the hard substance located underneath the enamel of the tooth. Dentine has a yellow color.
61. Dermis: the layer of the skin located underneath the epidermis. The dermis contains blood vessels, nerve endings, hair
follicles, sweat glands and oil glands.
62. Diabetes: a non-infectious disease characterized by the inability to control blood glucose levels due to a deficiency in the
hormone, insulin.
63. Diaphragm: the organ that separates the thoracic cavity from the abdomen. The diaphragm moves down into the abdomen
when you inhale. This creates more space for the lungs to expand.
64. Diarrhea: a symptom characterized by excessive water loss in stool due to an infection in the intestines. Cholera and
typhoid fever cause diarrhea.
65. Diastole: the denominator in the fraction that indicates blood pressure. A healthy diastole is less than 80 mmHg.
66. Dietary fiber: non-digestible complex carbohydrates that stimulate peristalsis of the intestines. Dietary fiber helps to clean
the intestinal tract. Eating more fiber can help to prevent constipation.
67. Diffusion: the movement of molecules from a higher to lower concentration without using ATP (energy).
68. Digestion: the breaking down of large, complex molecules into simple, small molecules. Digestion is important so that food
particles can be small enough to be absorbed into cells.
69. Distillation: the process by which impure water is boiled and only the water evaporates. The water vapor is then cooled
(condensation) to return to its liquid form. This is a method of purifying water.
70. Discontinuous variation: a trait that is expressed in either one form or the next; for example, male or female; blood type A,
B, AB or O.
71. Down syndrome: a genetic disorder characterized as a trisomy 21. There is an extra chromosome contributed usually by the
egg. Older women are more likely to produce eggs that have an incorrect number of chromosomes, thereby resulting in a
zygote containing an incorrect diploid number.
72. Duodenum: the first part of the small intestines that is about 10 inches long. A lot of absorption occurs here.
73. Egestion: also known as defecation, or when feces are forced out through the anus
74. Egg: a haploid cell; also called a gamete or sex cell; a human egg cell contains 23 chromosomes.
75. Embryo: the multicellular stage after the zygote divides. The embryo implants itself onto the upper-back wall of the uterus.
After two months of pregnancy, it is then called a fetus.
76. Enamel: hardest substance in the human body. The outermost layer of a tooth’s crown.
77. Endoplasmic reticulum: the rough endoplasmic reticulum produces proteins; the smooth endoplasmic reticulum produces
fats.
78. Enzymes: also called catalysts; they bind to substrates to form an enzyme-substrate complex. Enzymes perform either
catabolism (breaking down molecules) or anabolism (building larger molecules).
79. pH effect: living things require a specific pH range in order to survive. Even in our bodies, specific enzymes require specific
pH conditions to perform optimally. For example, pepsin, which is an enzyme in the stomach that breaks down proteins,
can only work well at a very acidic (low) pH (≤2). Amylase in the mouth, works its best at a pH close to 7. This is why when
we swallow food, the amylase enzyme stops working because the stomach’s pH is much less than 7. NOTE THAT CHANGE IN
TEMPERATURE ALSO AFFECTS ENZYME ACTIVITY.
80. Epidermis: the uppermost layer of the skin that is composed of dead, keratinized cells to protect against pathogens from
entering the body.
81. Epididymis: part of the male reproductive system where sperm cells mature and may be stored.
82. Eutrophication: An unnatural increase in the growth of blue-green algae (cyanobacteria) due to the addition of phosphates
and nitrates to ponds and coastal waters. Detergents, insecticides and raw sewage have phosphates and nitrates.
83. Excretion: performed by the kidneys to remove poisonous wastes from the body in the form of urine.
84. Exocrine glands: contain ducts that do not lead into the circulatory system. For example, the pancreas produces enzymes
and bicarbonate that enter the pancreatic duct that leads into the small intestines. These digestive juices do not enter the
blood stream.
85. Fallopian tubes: site for fertilization: the sperm cell fuses with the egg cell to form a zygote.
86. Family planning: methods of controlling when to have children and how many children to have.
87. Fats: also called lipids, which contains vast amounts of energy that is stored.
88. Fertilization: the process that occurs in the upper fallopian tubes; the male gamete fuses with the female gamete to form a
zygote.
89. Fungi: commonly known as mold. Differ from plant cells in that fungi cell walls have chitin, not cellulose. The fungi are
saprobes, or decomposers. They do not make their own food, but feed off of dead and decaying organic matter.

FUNGI ARE VERY IMPORTANT FOR THE RECYCLING OF NUTRIENTS IN THE CARBON CYCLE

90. Gall bladder: small, green sac underneath the right lobe of the liver. The gall bladder stores bile. When fat is in the small
intestines, bile is secreted into the cystic duct, then into the common bile duct that leads into the duodenum.
91. Gastroenteritis: damage to the walls of the stomach and intestines causing inflammation and sometimes bleeding. Typhoid,
cholera and amoebic dysentery are all examples of gastroenteritis. Symptoms include diarrhea, fever and abdominal
cramping.
92. Gene: made up of two alleles. You receive one allele from your mother and the other from your father. A gene may be one
of three versions: homozygous dominant, homozygous recessive or heterozygous.
93. Genotype: the DNA make-up of an individual. DNA is located in the nucleus of your cells. The genotype is the code for one’s
phenotype.
94. Global warming: due to excess burning of fossil fuels (gas, oil and coals), carbon dioxide levels in the atmosphere become
high. The carbon dioxide forms a “blanket” around the planet, thereby preventing heat from escaping. This causes the
planet’s temperature to increase.
95. Glomerulus: network of capillaries associated with Bowman’s capsule of the nephron. Filtration of the blood occurs in the
glomerulus to clean the blood.
96. Glucagon: a hormone produced by alpha cells of the pancreas. Glucagon increases blood glucose levels. The glucose is
pulled out of the liver. Glucagon is antagonistic to insulin.
97. Glucose: a simple, reducing sugar. Glucose is used in cellular respiration to produce carbon dioxide, heat, water and ATP.
When glucose is mixed with Benedict’s reagent and heated, it turns bright orange.
98. Glycerol: the backbone molecule of a triglyceride and phospholipid.
99. Glycogen: a complex sugar stored in the liver. Glycogen is broken down into glucose when blood sugar levels drop below
normal.

100. Gonorrhea: sexually transmitted disease that is usually asymptomatic in women. Symptoms include burning and itching
when urinating; signs include pus discharge, redness and inflammation of the genitals. Antibiotics are used to treat gonorrhea.

101. Greenhouse effect: the carbon dioxide layer that forms around the planet acts like a glass ceiling (similar to that of a
greenhouse) and prevents heat from escaping.

102. Hemoglobin: a red pigment that binds to oxygen, carbon dioxide and carbon monoxide. Hemoglobin is a protein that
covers red blood cells and contains iron that binds the oxygen, etc.

103. Hemophilia: a genetic disorder that affects mostly males. The genetic mutation is on the X-chromosome. This disorder is
characterized by the inability to form a blood clot, resulting in bleeding to death.

104. Haploid: a cell that contains half of the number of chromosomes (n). Sperm and egg cells are haploid.

105. Heart attack: caused by plaque build-up in the coronary arteries that supply blood to the heart muscles. Blockage of blood
flow prevents oxygen from getting to the muscle cells, resulting in death of the heart cells.

106. Herbivore: a consumer that eats only plants.

107. Herpes: a sexually transmitted disease caused by the herpes simplex virus. Symptoms include itching and pain; signs
include blisters that form ulcers. There is no cure. Antiviral treatments help to reduce the severity of symptoms and frequency
of outbreaks.

108. HIV: Human Immunodeficiency Virus. This virus destroys specific white blood cells called helper T-cells. Without helper T-
cells, the immune system is severely weakened, resulting in a condition called AIDS (Acquired Immune Deficiency Syndrome). An
AIDS patient is susceptible various infections, including the common cold, fungi and other viruses.

109. Homeostasis: the ability to maintain a steady state of wellness. A person who has a fever is not in homeostasis.

110. Hydrochloric acid: the chemical produced by parietal cells of the stomach lining that kills germs, activates the enzyme
pepsin and softens the predigested food.

111. Hydrolysis: the process by which enzymes are used and water is added to break up larger molecules into smaller ones.
Hydrolysis is a catabolic reaction.

112. Hypertension: high blood pressure; (a systolic value greater than 120 and a diastolic value greater than 80).

112. Hypothalamus: the master gland of the endocrine system. It reads information from the blood and produces various
hormones, including ADH, oxytocin, GnRH, GHRH, etc.

113. Ileum: the 3rd and final segment of the small intestines that is about 2 – 4 meters longs.

114. Implantation: the attachment of the embryonic stage called the blastula to the endometrium of the upper-back wall of the
uterus.

115. Incisors: the “front” teeth used for biting.

116. Insertion site: where the tendon is attached to movable bone. For example, the insertion site for the biceps muscle is the
radius.

117. Insulin: a hormone produced by beta cells of the pancreas. This hormone is secreted after you eat a meal to lower blood
glucose levels. INSULIN IS A PROTEIN.

118. Iris: the color of the eye that contains circular and radial muscles to contract and dilate the pupils, respectively.

119. IUD: Intrauterine device used as a contraceptive method to block sperm from entering the fallopian tubes; copper IUDs
also kill sperm cells.

120. Knee-jerk reflex: an example of a reflex action that does not involve the brain.

121. Legumes: plants that have nodules in their roots containing nitrogen fixing bacteria. The bacteria convert pure nitrogen
into ammonia (a usable form of nitrogen).

122. Leptospirosis: a.k.a. Weil’s disease. A very painful disease characterized by headache, limb and muscle plains; fever; kidney
and liver failure. This disease is caused by the bacteria, Leptospira. The bacteria are found in rat urine, infected flea bites; dogs
and bats.

123. Ligament: connective tissue that connects bone to bone. Ligaments are yellow and can stretch.
124. Lipase: an enzyme produced by the pancreas. This enzyme breaks down lipids (fats) into glycerol and fatty acids.

125. Liver: an organ in the abdominal cavity that produces bile, a chemical that emulsifies fat in the small intestines. The liver
also detoxifies the blood of alcohol and other drugs. The organ also stores glucose in the form of glycogen.

126. Long-sightedness: the eye ball is too small and/or the lens is too thin. Consequently, you can see objects far away, but not
near. The image is projected behind the retina.

127. Lymphatic system: produces white blood cells (leukocytes).

128. Lymphocytes: specific white blood cells, such as T-cells and B-cells. Remember that HIV destroys Helper T-cells.

129. Maltase: an enzyme that breaks down maltose into two glucose molecules.

130. Marijuana: a.k.a. cannabis. Produces euphoria (a “high”), that follows a feeling of depression when the drug wears off.
Marijuana causes the pupils to dilate and the person feels apathy (a loss of interest all around); memory loss and unpleasant
hallucinations may occur.

131. Mastication: to chew or grind food with teeth. It is a form of mechanical digestion.

132. Medulla Oblongata: a.k.a. “brain stem”. It controls involuntary actions, such as your heart rate and breathing.

133. Meiosis: a process involving two cell divisions that result in four haploid cells (gametes). Meiosis takes place in the ovaries
of the female and testes of the male.

134. Menstrual cycle: 28 days long; bleeding during the first week; ovulation on the 14 th day.

135. Mitochondria: an organelle in a cell that performs cellular respiration. Glucose + Oxygen  Carbon dioxide + Water + Heat
+ ATP (energy). Muscle cells would have more mitochondria than skin cells because muscle cells require more ATP for lifting,
etc.

136. Molars: teeth used for chewing and grinding food.

137. Monohybrid inheritance: when a certain phenotype is caused by only one gene. For example, albinism.

138. Motor neuron: a nerve cell that carries an electrical impulse from the CNS to the effector muscle to cause a response.

139. Mutation: when the base sequence in the DNA is changed, resulting in a change in the protein.

140. Negative feedback: the “off” switch for an action. For example, when blood glucose levels normalize, insulin secretion by
the pancreas decreases. Another example would be testosterone switching itself off.

141. Nephron: tubule in the kidney that performs filtration, reabsorption and secretion. There are about one million nephrons
per kidney.

142. Neuron: a cell of the nervous system. A neuron contains dendrites and an axon. The dendrites receive a chemical message
and the axon relays the chemical message to the post-synaptic neuron.

143. Neurotransmitter: a chemical (protein) that is released by the axon terminal to excite a post-synaptic neuron or effector
muscle. For example, acetylcholine is a neurotransmitter that excites skeletal muscles to contract.

144. Night-blindness: caused by a deficiency in vitamin A (retinol).

145. Nitrifying bacteria: convert ammonia into nitrites and finally into nitrates that are absorbed by plants. Nitrosomonas
converts ammonia into nitrites. Nitrobacter convert nitrites into nitrates.

146. Non-reducing sugar: does not turn orange when heated and mixed with Benedict’s reagent. An example is sucrose.

147. Nucleus: organelle in the cell that contains DNA. The DNA is generally in the form of chromosomes.

148. Oesophagus: tube that connects the mouth to the stomach. Peristalsis causes the bolus of food to move down the
oesophagus.

149. Oestrogen: hormone produced by the ovaries that causes the endometrium to grow and contributes to the development of
female secondary sex characteristics.

150. Omnivore: an animal that eats both meat and plants. Human are omnivores.

151. Optic nerve: the neuron that transmits an electrical impulse from the retina of the eye to the occipital lobe of the
cerebrum.

152. Organelles: structures found in cells that carry out specific functions. For example, the nucleus, rough ER, smooth ER,
mitochondria, golgi apparatus and chloroplast.
153. Origin: the site of tendon attachment where there is less movement of the muscle.

154. Osmosis: the movement of water from a higher concentration to a lower concentration without using ATP (energy). The
water moves to a higher concentration of solute.

155. Ovaries: organs that produce the female gametes (eggs). The ovaries secrete estrogen and progesterone.

156. Oviducts: a.k.a. fallopian tubes where fertilization occurs.

157. Oxygenated blood: a high concentration of oxygen and a low concentration of carbon dioxide. The blood is red.
Oxygenated blood travels from the lungs via the pulmonary veins to the left atrium of the heart.

158. Oxytocin: hormone produced by the hypothalamus and stored by the posterior pituitary gland. Oxytocin causes muscle
contractions of the uterus during labor and milk let-down in the nursing mother.

159. Pacemaker of the heart: the S.A. node (sinoatrial node) which is where the electrical impulses begin to causes heart
contractions. The S.A. node is located in the upper section of the right atrium.

160. Pancreas: organ located behind the stomach. The pancreas produces insulin to lower blood glucose levels; and glucagon to
raise blood glucose levels. The pancreas also produces digestive enzymes, such as amylase, protease, lipase and nucleus that
break down starch, proteins, fats and DNA, respectively.

161. Pasteurization: a process by which milk is heated to kill bacteria.

162. Pathogen: something that is harmful to the body, such as a virus or bacteria. HIV is a pathogen. Leptospira is a pathogen.
The dengue virus is a pathogen.

163. Penicillin: an antibiotic used to kill bacteria. Penicillin is produced by mold (fungus).

164. Pepsin: an enzyme produced by chief cells of the stomach. Pepsin breaks down proteins into smaller proteins (shorter
amino acid chains).

165. Peripheral Nervous System: consists of the cranial nerves and spinal nerves.

166. Peristalsis: involuntary muscle contractions that push food along the digestive tract. Peristalsis occurs in the esophagus,
stomach, small intestines, large intestines and rectum.

167. Phagocyte: a white blood cell, such as a macrophage, that performs phagocytosis. This process involves “eating” the
pathogen.

168. Phenotype: the outward appearance and behavior of an organism. The phenotype is determined by both the genotype and
the environment.

169. Photosynthesis: a process occurring in the chloroplast of plant cells that requires chlorophyll (green pigment) to absorb
sunlight.

Sunlight + Carbon Dioxide + Water  Glucose + Oxygen

NOTICE THAT PHOTOSYNTHESIS IS THE OPPOSITE OF CELLULAR RESPIRATION

170. Pit latrine: a conservancy system that does not use water to flush away human feces. The feces are deposited into a pit that
is about three meters deep. The feces are decomposed by bacteria in the soil. A pit latrine is similar to a borehole latrine, except
the borehole latrine is much deeper (hole is about seven meters deep).

171. Pituitary gland (anterior): produces FSH (follicle stimulating hormone) that causes the follicle to grow during the first two
weeks of the menstrual cycle; it also produces LH (luteinizing hormone) that causes the follicle to rupture on the 14 th day
(ovulation). The anterior pituitary gland produces other hormones, such as TSH, GH and prolactin.

172. Placenta: organ that separates the mother’s blood from the fetus’ blood. This may prevent any pathogens in the mother’s
blood from reaching the fetus. The placenta also contains capillaries to facilitate the exchange of nutrients and wastes between
the mother and fetus.

173. Plasmolysis: when a plant cell loses was (turgor pressure becomes low) because water is moving towards the salt or sugar
on the outside.

174. Platelets: pieces of cells that stick to any damaged sections of a blood vessel’s wall. This creates a blood clot that prevents
bleeding.

175. Producers: a.k.a. Autotrophs. Organisms that perform photosynthesis and therefore make their own food, such as plants.
Producers make up most of an ecosystem’s biomass.

176. Progesterone: hormone produced by the corpus luteum to keep the endometrium thick during the last two weeks of the
menstrual cycle. When the corpus luteum dies and progesterone levels drop, the endometrium sheds.
177. Prostate gland: produces a milky alkaline substance to protect the sperm from the acidic vagina. The prostate also
contracts to cause ejaculation.

178. Prostate cancer: tumor growth in the prostate that causes the prostate to become enlarged. This may disrupt the flow of
urine from the urinary bladder; and may also disrupt ejaculation.

180. Protein synthesis: a process that occurs on ribosomes of the rough ER. Messenger RNA (mRNA) is translated on ribosomes
to produce amino acid chains that are then folded to form a completed protein (eg. Hemoglobin).

181. Proteins: molecules made up of amino acids.

182. Pulmonary circulation: blood flow from the right side of the heart to the lung and then to the left side of the heart.

183. Pulmonary vein: blood vessel that carries oxygenated blood from the lung to the left atrium of the heart.

184. Pulp cavity: the part inside of a tooth containing blood vessels and nerves.

185. Rabies: a virus found in the saliva of bats. It is transmitted to humans by being bitten by a bat. The virus multiplies in the
human muscles and then affects the brain, causing paralysis of the throat, hydrophobia and eventually death. Immediate and
progressive vaccinations are required.

189. Recessive allele: represented by a lower case letter; and is usually masked by the dominant allele. The recessive allele can
only be expressed in the phenotype if there are two copies (homozygous recessive).

190. Red blood cells: a.k.a. erythrocytes. Produced in the red bone marrow; covered in a protein called hemoglobin that carries
iron. The iron binds to oxygen, carbon dioxide and also carbon monoxide. Binding of oxygen to the iron causes the blood to turn
red.

191. RECYCLE, REDUCE, REUSE: the three “Rs” of conserving our resources, such as paper and petroleum. This also reduces
pollution.

192. Reducing Sugars: turn orange when heated and mixed with Benedict’s reagent. Glucose, fructose, galactose, maltose and
lactose are reducing sugars. SUCROSE IS NOT A REDUCING SUGAR.

193. Reflex action: a response to a stimulus that does not involve the brain. An electrical impulse moves along a sensory neuron
towards the spinal cord, then down a motor neuron to the effector muscle.

194. Renal artery: carries oxygenated and unfiltered blood into the kidneys.

195. Renal vein: carries deoxygenated and filtered blood out of the kidneys.

196. Retina: the back layer of the eye that contains cells called rods and cones. Rods are for night vision and cones are for seeing
color.

197. Ribosomes: structures in a cell where protein synthesis occurs. Ribosomes can be attached to the ER, or be “floating” in the
cytoplasm. It is called the “Rough ER” because the attached ribosomes make it look rough.

198. Rickets: disease characterized by soft bones due to a deficiency in vitamin D.

199. Ringworm: a skin infection caused by a fungus. Athlete’s foot is an example of ringworm. Washing feet with soap, wearing
clean socks, keeping in-between the toes dry and not wearing other people’s shoes are preventative measures.

200. RNA: Ribose nucleic acid. RNA is produced in the nucleus by a process called transcription. The DNA is transcribed into
mRNA that is then exported to the ribosomes to be translated into proteins.

201. Roughage: a.k.a. dietary fiber. This cannot be digested and therefore cleans out the digestive tract and stimulates
peristalsis for defecation. Roughage is abundant in fruits and vegetables.

202. Salivary amylase: enzyme produced by the salivary glands that breaks down starch into maltose in the mouth.

203. Scabies: a mite transferred by skin contact or dirty bedding. The mite burrows under the skin’s surface.

204. Scurvy: a disease characterized by bleeding gums and losing teeth due to a vitamin C deficiency.

205. Sebaceous gland: located in the dermis; produces oil that lubricates the dead epidermis.

206. Seminal vesicles: produce fructose, zinc and 70% of the seminal fluid. The fructose is the sugar necessary that will provide
energy to the sperm cells.

207. Sensory neuron: carries an electrical impulse from the stimulus to the central nervous system.
208. Sex inheritance: there is an equal chance of conceiving a boy or girl. The egg cell always carries an “X” chromosome. The
sperm cell carries either an “X” or “Y” chromosome. If the zygote is “XX” then it is female; if the zygote is “XY” then it will be a
male.

209. Sexual reproduction: involves fertilization of an egg by sperm to form a zygote.

210. Short-sightedness: a.k.a. nearsightedness. The person can see near objects, but not far away. This is due to the eyeball
being too large and/or the lens being too thick. Concave or minus lens are used to rectify this problem.

211. Sickle cell anemia: a genetic disorder caused by a point mutation (a single base error). As a result, the red blood cells are
crescent or moon shaped and cannot carry oxygen efficiently. These red blood cells stick together and cause blood clots. To
express sickle cell anemia, you must possess the genotype, homozygous recessive (ss).

212. Sign: an objective observation that is more helpful in diagnosing a disease; for example, inflammation, pus, red eyes or
bleeding gums.

213. Synapse: the space between the presynaptic and postsynaptic neuron. Neurotransmitters cross the synapse and bind to
their receptors to excite the postsynaptic neuron.

214. Spirometer: a device used to measure how well your lungs are working.

215. Starch: a complex carbohydrate made up of a chain of glucose molecules. Starch turns blue-black when mixed with iodine.
Starch is too complex to cross a cell’s membrane. Starch is stored in plants.

216. Sulphur dioxide: gas produced by burning fossil fuels. Sulphur dioxide causes acid rain to form; corrodes metals; forms
‘smog’ that causes lung damage and bronchitis.

217. Suspensory ligaments: fibers that pull on the lens so that the eyes can adjust to seeing near and far objects. The suspensory
ligaments are animated by the ciliary body.

218. Symptoms: can only be described by the patient; for example, dizziness, headaches, itchiness and fatigue.

219. Synovial fluid: fluid in the joint capsule that absorbs shock and lubricates the articular cartilage.

220. Syphilis: a venereal disease caused by the bacterium, Spirilla. Signs include a hard, red ulcer on the genitals; later on, if
untreated, the person suffers from brain damage and insanity. Antibiotic are used to treat Syphilis.

221. Systole: the pressure against the wall of the artery when the ventricles contract. Systole is the numerator of the fraction.

222. Tapeworms: flatworms attached by hooks and suckers to the inside wall of the small intestines. People become infected
with tapeworms by eating undercooked meat. Sufferers are always hungry, thin, pale and weak because the worms absorb the
nutrients in the small intestines.

223. Tendon: connective tissue that attaches muscle to bone. Unlike ligaments, tendons do not stretch.

224. Testes: produce testosterone required for sperm production and male secondary sex characteristics.

225. Threadworms (round or pin worms): spread by ‘anus to mouth’. The worms attach themselves to the inside wall of the
small intestines and eventually lay their eggs near the anus. The eggs are picked up and infect another person.

226: Thyroid gland: endocrine gland that produces T3 and T4 hormones which speed up your metabolism. The thyroid also
produces calcitonin that prevents calcium loss from the bones.

227: Tongue rolling: an example of discontinuous variation. There are two distinct groups (those who can and those who cannot
roll their tongues). There is no “in between” group.

228. Tooth decay: caused by acid penetrating the enamel and dentin of a tooth. When bacteria in the mouth metabolize sugar,
they produce lactic acid.

229. Trachea: a.k.a. Windpipe. A non-collapsible tube supported by cartilage. The tube leads into the right and left bronchi.

230. Transpiration: water loss from the leaves of plants. Leaves have tiny holes called stomata that open and close. When the
stomata open, water and oxygen exit the leaf.

231. Triceps: antagonistic to the biceps. The triceps allow extension of the arm.

233. Tricuspid valve: prevents the backflow of blood into the right atrium.

234. Trypsin: a protease (protein digesting enzyme) produced by the pancreas and secreted into the small intestines. Trypsin
breaks down proteins into shorter amino acid chains.

235. Tuberculosis: a disease caused by bacteria in very overcrowded regions. The bacteria are spread by respiratory droplets
from coughing. The lungs are destroyed causing the infected to cough up blood. Vaccinations are given to prevent the disease.
Antibiotics are used to treat it.
236. Turgor pressure: the pressure applied by water on the inside wall of a plant cell. Plant cells exposed to a hypotonic solution
will display high turgor pressure because water moves into the cells; plant cells exposed to a hypertonic solution (salty) will lose
water and thereby lose turgidity.

237. Typhoid: caused by bacteria in sewage (feces) that end up in the water supply. Symptoms include dehydration and stomach
pains. Signs include severe diarrhea, vomiting, inflammation of the intestines and fever. Typhoid symptoms and signs are similar
to those of cholera.

238. UHT (ultrahigh temperature) sterilization: heating foods to temperatures above 135 degrees Celsius to create aseptic
conditions (bacteria free). Pasteurization (boiling milk at 63 degrees Celsius for 30 minutes) is another process that kills most
bacteria. At home, boiling in water at 100 degrees Celsius is generally effective in killing most pathogens.

239. Ureter: tube leading from the kidney to the urinary bladder.

240. Urethra: tube that is the exit for sperm and urine in the male; only urine in the female.

241. Uterus: produces a temporary lining called endometrium for implantation of the embryo. Estrogen produced by the ovaries
is required for the endometrium to grow. The embryo implants itself on the upper-back wall of the uterus.

242. Vaccination: contains a harmless form of the bacteria or virus. The body’s immune system recognizes the antigen and
makes the antibodies for that antigen. B-cells mature into plasma cells that produce antibodies. A specific antibody is produced
for a specific antigen.

243. Vas deferens: location where mature sperm are stored. The vas deferens are cut in a procedure called a vasectomy. This is
a contraceptive method.

244. Vasoconstriction: when an artery’s diameter is reduced to decrease blood flow. This happens to arteries in the dermis
when we are feeling cold. This prevents excess heat from being lost through the skin.

245. Vasodilation: when an artery’s diameter widens to increase blood flow. This happens in arteries in the dermis when we are
feeling warm. This allows excess heat to be lost through the skin. Remember that heat is lost from the body by radiation,
conduction and convection.

246. Vectors: animals (mainly insects) that carry pathogens to the body. For example, the vector for dengue is a mosquito,
Aedes aegypti.

247. Vena Cava: (Superior and Inferior). Blood vessels that carry deoxygenated blood to the right atrium of the heart.

248. Venereal disease: a disease that is contracted only by sexual intercourse; for example, gonorrhea and syphilis. HIV IS NOT
VENEREAL BECAUSE IT CAN BE CONTRACTED BY OTHER MEANS.

249. Ventricles: (right and left). Receive blood from the atria. The right ventricle pumps deoxygenated blood into the pulmonary
arteries. The left ventricle pumps oxygenated blood into the aorta.

250. Villus: “finger-like” projections in the small intestines that increase the surface area for absorption.

251. Vital capacity: measured by breathing in as much as possible and exhaling as much air as possible.

252. Vitamin A: abundant in carrots, fish, eggs and green leafy vegetables. Vitamin is important for proper eye function, healthy
mucus membranes and strong bones and teeth.

253. Vitamin B: a complex of vitamins required for making energy. Vitamin B is abundant in fruits, whole grain, vegetables and
eggs.

253. Vitamin C: required for making collagen to keep gums and blood vessel walls healthy; vitamin C is also necessary for fast
healing of wounds. It is also an antioxidant that helps to prevent cancer. Fruits are high in vitamin C.

254. Vitamin D: required for the absorption of calcium and phosphate, thereby maintaining strong bones and teeth. Diary, such
as milk and cheese are high in vitamin D.

255. White blood cells: required to fight pathogens. White blood cells make up the immune systems. Macrophages are specific
white blood cells that perform phagocytosis to engulf the pathogen. Plasma cells produce antibodies for specific antigens.
Cytotoxic T-cells produce chemicals that destroy the pathogen. Memory B-cells and Memory T-cells remain in your blood in case
the same pathogen was to reenter.

256. Y-chromosome: carried by 50% of all sperm. Only males have a Y-chromosome since males have an “XY” genotype.

257. Zygote: a diploid cell containing 46 chromosomes. A zygote contains DNA from both parents. The zygote undergoes mitosis
to form two cells, then four cells and eventually a blastula that implants itself on the upper-back wall of the uterus .