Transportation:

Activity 6.7

OB SER VATION: Haemoglobin range varies with age and sex

Children of age 6 to 12 yrs – 11.5 to 15.5 g/dl

Adult females – 12.1 to 15.1 g/dl

Adult males – 13.6 to 17.7 g/dl

Calves: average 10.5

Cow: male 8-12 female 10 to 15

Buffalo: Male 12.5 to 14.5 Female 11.5 to 13.5

EXP LANATION: Haemoglobin is an iron-containing red pigment present in red blood cells. A
person with lesser haemoglobin looks pale with low energy. Spinach, beetroot, beans and lentils
are the rich sources of iron.

CAU SE OF REGIONAL VARIATION: Haemoglobin varies from place to place and depends
on environmental condition. If there is low oxygen concentration in the air, then there is higher
haemoglobin content. For example, people going to high altitude gets more haemoglobin value
in 2 to 3 month.

Human Heart : The sequence of events which take place during the completion of one heart is
called cardiac cycle . It involves repeated rhythmic contraction and relaxation of heart muscles.
Contraction is called systole. Relaxation is called diastole.

1) Oxygen rich blood from the lungs enter the left atrium. The left atrium relaxes
when it is collecting the blood. Then it contracts while next chamber i.e. left
ventricle expands so that blood is transferred to it.
2) From left atrium the blood is transferred to left ventricle through bicuspid valve.
From the left ventricle the blood is pumped to various parts of body through
aorta (largest artery). Oxygenated blood from lungs enters the left atrium
through pulmonary veins.
3) The de- oxygenated blood from various parts of the body is poured into right
atrium through large veins called vena cava.
 4) As the right atrium contracts, the corresponding right ventricle expands and
blood through tricuspid valve gets collected . It then pumps it to the lungs for
oxygenation by pulmonary arteries. In the lungs this blood becomes oxygenated
and return to the heart by pulmonary veins.

The blood circulation in human heart is double circulation. This means that blood passes
through heart twice. One circulation involves entry of blood from all body parts to heart. This
blood is deoxygenated which goes to lungs for oxygenation. The second circulation involves
entry of oxygenated blood from lungs to heart and then to all body parts.

The force that blood exerts against the walls of a vessel is called blood pressure. It is measured
by Sphymamometer. The pressure of blood inside the artery during ventricular contraction is
called systolic pressure.

The pressure of blood inside artery during ventricular relaxation is called diastolic pressure.

TRANSPORTATION IN PLANTS :
Soil is the natural and richest source of raw material for plants.

Raw materials like nitrogen, phosphorous and other minerals are absorbed by plants
from soil by roots.

A group of special cells forming vascular tissue transport water and nutrients to all the
cells of the plants.

Two types of vascular tissues are xylem and phloem.

Xylem transports water and minerals obtained from the soil.

Phloem transports products of photosynthesis from the leaves to other parts of the
plant.
Vessels, tracheids of the roots, stems and leaves are connected to form a continuous
system in xylem cells to transport water to all the parts of the plants.

The loss of water in the form of water vapor is called

Importance of transpiration-

o Regulates temperature.
o Helps in absorption of water and upward movement of water and minerals.
Phloem transports soluble products of photosynthesis, amino acids, and other
substances.

The transport of soluble products of photosynthesis is called translocation.

The substances are transported to the storage organs of roots, fruits and seeds.

The translocation takes place in the sieve tubes with the help of adjacent companion
cells.

The movement of substances is bidirectional i.e both upward and downward.

Q19 What are the components of the transport system in human beings? What are the
functions of these components?

Ans: The transport system (circulatory system) in human beings mainly consists of heart, blood
and blood vessels.

i. (i) Function of heart : The heart receives deoxygenated blood from the body parts and
pumps it to lungs for enriching with oxygen. It receives purified blood from lungs and
pumps it around the body.
(ii) Function of blood : Blood transports oxygen, carbon dioxide, digested food,
hormones and nitrogeneous waste like urea. It also protects the body from diseases and
regulates the body temperature.
(iii) Function of blood vessels : The blood pushed by the heart flows through the blood
vessels (arteries, veins and capillaries) and also comes back to the heart through them.

Q20 Why is it necessary to separate oxygenated and deoxygenated blood in mammals and
birds?

Ans: Separation of oxygenated and deoxygenated blood allows good supply of oxygen to the
body. This system is useful in animals that have high energy requirement. Mammals and birds
constantly need oxygen to get energy to maintain their body temperature constant.

Q21 What are the components of the transport system in highly organized plants?

Answer: The plant transport system in highly organized plants contains following:
 a. Xylem: To transport water and minerals from roots to other parts.
b. Phloem: To transport food from leaves to other parts.

Q22 How are water and minerals transported in plants?

Answer: Water and minerals are transported from roots. At the level of roots the root
pressure helps in rise of water and minerals up to some height. After that there is complex
mechanism at work. The transpiration taking place in leaves creates a suction effect which
pulls up water in minerals to great heights.

Q23 How is food transported in plants?

Answer: Food is transported in plants through phloem. The transport in phloem is an active
process and involves use of energy. The energy in the form of ATP created osmotic gradient
which results in transportation of food through phloem.

Excretion:
o The biological process of removal of harmful nitrogenous metabolic waste from the
body is called excretion.
o Unicellular organisms excrete by diffusion and multicellular organisms use
specialized organ to perform same function.
Excretion in human beings
o A pair of kidneys, a pair of ureters, a urinary bladder and a urethra constitutes the
human excretory system.
o Kidneys are present on either side of the backbone in the abdomen.
o Kidneys produce urine and urine from kidney passes through the ureters into the
urinary bladder and remains stored their until it is released through the urethra.
Human excretory system :

o Urine is produced to filter out waste products from the blood.

o Nephrons are basic structural and functional unit of kidney.
o Cluster of thin walled blood capillaries called glomerulus in the nephron filtrate the
urine and each cluster is associated with cup shaped end of a tube called Bowman’s
capsule
o Substances like glucose, amino acids, salts and a major amount of water is
selectively reabsorbed from the initial filtrate as the urine flows along the tube.
o Reabsorption depends on the amount of excess water in the body and dissolved
waste to be excreted.
o The urine from kidney enters the long tube called ureter.
o Ureter connects the kidney with the urinary bladder and urine from the kidney is
passed to urinary bladder and stored in the bladder.
o When the pressure in the expanded bladder leads to the urge to urinate, the urine is
passed out through urethra.
Excretion in plants :
o Oxygen, a waste product of photosynthesis is released.
o Excess water is removed by transpiration.
o Some waste products may get stored in the leaves which fall off.
o Many waste products are stored in vacuoles.
o Some waste products are stored as resins and gums in old xylem.
o Plants excrete some waste materials into the soil around them.

Q 24 Describe the structure and functioning of nephrons.

Answer: The nephron is the functioning unit of kidneys. Nephron consists of a capsule shaped
structure called Bowman’s capsule. The filtration of blood takes place in Bowman’s capsule
under very high pressure. After that waste product goes to a network of collecting tubules
which finally meet in a common collecting duct. The collecting duct meet in ureter which
carries urine to the urinary bladder.

Q 25 What are the methods used by plants to get rid of excretory products?

Answer: Plants get rid of carbon dioxide and oxygen through diffusion. Old branches and
leaves are shed off when they become useless. Plants release some waste products through
roots also. Some waste products are deposited near bark as raisins or gums.

Q26 How is the amount of urine produced regulated?

Answer: The kidney has a mechanism to reabsorb water from the filtrate. This depends on
how much water is left in the body and in the filtrate. The comparative concentration of
water gives a signal to the brain which then takes the required corrective action of either
reabsorbing water or releasing more water. Thus the amount of urine formation is regulated
by kidneys.
Q 27 What would be the consequences of a deficiency of haemoglobin in our bodies?
Answer:
Due to the deficiency of haemoglobin in blood, its oxygen carrying capacity decreases. As a
result the production of energy by oxidation will become slower. Therefore, one would fall sick
and would feel fatigue most of the time.

Q 28 Describe double circulation in human beings. Why is it necessary ?

Answer:
In our heart blood enters twice and also pumped out twice from the heart. The deoxygenated
blood from the body is brought to the right atrium through vena cava from where it is sent to
right ventricle. From right ventricle, the blood is pumped to the lungs for oxygenation through
pulmonary artery. The oxygenated blood from lungs again enters the left atrium of the heart
through pulmonary veins. From left atrium it is send to left ventricle, from where this
oxygenated blood is pumped to different parts of body through the arteries. In this way the blood
flows through the heart twice, that’s why it is called ‘double circulation’.

Necessity of double circulation: The right side and the left side of the human heart are useful to
keep deoxygenated and oxygenated blood from mixing. This type of separation of oxygenated
and deoxygenated blood ensures a highly efficient supply of oxygen to the body. This is useful in
case of humans who constantly need energy to maintain their body temperature.

Q.29 What are the differences between the transport of materials in xylem and phloem ?
Answer:

Xylem Phloem

1. Xylem conducts water and dissolved 1. Phloem conducts prepared food material from
minerals from roots to leaves and other parts. leaves to other parts of plant in dissolved form.

2. In xylem, the transport of material takes place 2. In phloem, transport of material takes place
through vessels and tracheids which are dead through sieve tubes with the help of companion
tissues. cells, which are living cells.
3. In xylem upward movement of water and 3. In translocation, material is transferred into
dissolved minerals is mainly achieved by phloem tissue using energy from ATP. This
transpiration pull. It is caused due to suction increases the osmotic pressure that moves the
created by evaporation of water molecules from material in the phloem to tissues which have less
the cells of a leaf. pressure

Q30 Compare the functioning of alveoli in the lungs and nephrons in the kidneys with respect to
their structure and functioning.
Answer:

Alveoli Nephron

1. Alveoli are functional unit of lungs. 1. Nephrons are functional unit of kidney.

2. A mature lung has about 30 crore alveoli. 2. A kidney has about 10 lakh nephrons.

3. Alveoli provide a wide surface for gaseous

3. The surface area of a nephron is not much more.
exchange.

4. The exchange of O2 and CO2 takes place 4. The Bowman’s capsule in nephron regulates the
through the network of capillaries in alveoli. concentration of water and salts.