GenBio Reviewer
LESSON 1: Cell Theory
Cell Theory
-Set of universally accepted ideas that living things are made up of cells
-Changes in understanding mediated by technology available to scientists
Anton Van Leeuwenhoek (1632-1703)
-Dutch Shopkeeper
-Observed protist, bacteria, and sperm (animalcules) movement using his microscope
-Father of microscope
Robert Hooke (1635-1703)
-Observed box-shaped structures in corks which he called “cells” as they reminded him of cells/rooms in
monasteries
Matthias Schleiden (1804-1881)
-Botanist (Plants)
-Concluded that all plant tissues are composed of cells
-Embryonic plant arose from a single cell
Theodor Schwann (1810-1860)
-Zoologist (Animals)
-Founded modern histology
-Cell as the basic unit of animal structure
Rudolf Virchow (1821-1902)
-Every living thing is made of vital units/cells
-Cells came from pre-existing cells
POSTULATES OF CELL THEORY
1. All organisms are made up of one or more cells
-Organisms made of one cell are called single-celled or unicellular
-Organisms made of more than one cell are multicellular
2. Cell is the basic unit of life
-Life takes place because of cells
-Organelles cannot sustain life on their own which is why they aren't the base unit of life
3. Cells arise from pre-existing cells
-Only cell that possibly didn't come from pre-existing cell was the first organism on earth
-For example; our cells came from parents
4. Energy flows in cells
5. Heredity info in DNA is passed from cell to cell
6. All cells have the same basic chemical composition
VIRUS IS NOT AN ORGANISM
-Doesn’t meet postulate no. 3
-Neither uni or multicellular
-Cannot reproduce on its own
-Parasite that NEEDS a host
-Strand of DNA or RNA with a shell made of protein
-Simpler than single celled organisms
BACTERIA IS AN ORGANISM
-Ubiquitous, mostly free living
-Consists of one biological cell
-Large domain of prokaryotic microorganisms
PROKARYOTIC CELLS/PROKARYOTES
-Unicellular
-No true nucleus
-Structures not bound by membrane
-One circular strand of DNA
-Small (1-10 μm)
-Has plasma membrane, cytoplasm, ribosomes, and DNA material
-DNA=Deoxyribonucleic Acid
-Double-stranded nucleic acid that contains genetic info for cell growth, division, and function
EUKARYOTIC CELLS/EUKARYOTES
-Multicellular
-Has nucleus
-Organelles enclosed by membrane
-Many DNA strands
-Large (10-100 μm)
-Has plasma membrane, cytoplasm, ribosomes, and DNA material
-DNA=Deoxyribonucleic Acid
-Double-stranded nucleic acid that contains genetic info for cell growth, division, and function
CELL ROLES AND FUNCTIONS
-All of these processes involve transformation of energy and matter
1. Nutrition
-Cells obtaining food molecules
2. Digestion
-Breaking down food particles using enzymes
3. Absorption
-Absorbing water, minerals, and other essential materials
4. Biosynthesis
-Organizing complex chemicals into simple building units or substances
5. Excretion
-Eliminating unnecessary by-products
6. Secretion
-Substances are synthesized and expelled from cells
7. Movement
-Locomotion using cilia or flagella
8. Irritability
-Responding or reacting to external factors
9. Respiration
-Breaking down glucose and producing ATP (Adenosine Triphosphate)
10. Reproduction
-Increasing cell number through cell division or copying and replicating its DNA
LESSON 2: Cell Organelles
1. Cell Membrane
-Semi-permeable
-Facilitates movement of molecules in our out the cell
2. Cytoplasm
-Viscous fluid/Jelly-like material where organelles are embedded
3. Nucleus
-Controls and regulates all chemical reactions within the cell
4. Mitochondria
-Powerhouse of the cell
-Center for cellular respiration
5. Vacuole
-Stores and releases various substances
-Cell enlargement and water balance
6. Endoplasmic Reticulum
-Series of tunnels
-Transport center
6A. Smooth ER
-No ribosomes
-Detoxifies lipids
6B. Rough ER
-Has ribosomes
-Releases newly made proteins
7. Ribosomes
-Protein factories
8. Golgi bodies
-Receives compounds
-Packaging and distributing compounds to parts of cell
9. Lysosomes
-Picking up bacteria, food, old organelles and breaking them into small, reusable pieces
10. Cytoskeleton
-Fibers made from proteins
-Provides structure and shape to cell
11. Cell Wall
-Rigid
-Composed of cellulose
-Gives plant cells box-like shape
12. Centriole
-Cilia and flagella
-Spindle fiber in cell division
Lesson 3: Animal Cell Types and Animal Tissues
Animal
-Multicellular eukaryotic organisms
-Kingdom Animalia
-Specialized tissues
-Heterotrophs (consuming organic material for energy)
-Voluntary movement and sensory response
Animal Cell Types
1. Skin
-Keratinocytes
-90%
-Produces keratin
-Melanocytes
-Produces melanin (skin color)
2. Muscle
-Myocytes
-Long, tubular cells
-Limb and organ movement
3. Blood
-Red
-Oxygen delivery
-White
-Destroys pathogens and other harmful substances
4. Fat
-Adipocytes/Lipocytes
-Fat and lipid (energy) storage
5. Nerve
-Neurons/Nerve cells
-Main cells of nervous system that carry messages and signals using dendrites and axons
6. Bone
-Osteocytes
-Majority of cells embedded within a fully formed lobe
7. Stem
-Develops into specialized cells
Tissue = Group of specialized cells that perform particular functions.
4 TYPES
1. Epithelial
-Tightly packed cells
-Outside the body as covering
-Linings of organs and cavities
-Barrier
-Secretes, Excretes, and Absorbs
-Protection
1A. Simple Squamous
-Plate-like cells
-Exchange of material through diffusion
-Lines Blood vessels & Lung Alveoli
1B. Stratified Squamous
-Multilayered
-Regenerates quickly
-Protects tissues from abrasions, drying out, and infection
-Skin, Mouth, Vagina
1C. Simple Cuboidal
-Cube-shaped cells
-Secretion
-Glands and Renal tubules
1D. Stratified Cuboidal
-Rare
-Protects Sweat, Mammary, and Salivary Glands
1E. Simple Columnar
-Brick-shaped cells
-Protection, Secretion, Active Absorption
-Lines Stomach and Intestines
-Has microvilli
1F. Pseudo-stratified Columnar
-Single-layer cells
-Lines Respiratory Tract
-Lined with cilia
2. Connective Tissue
-Fibrous cells
-Assists in support and protection of organs and limbs
-Joins or separates organs or parts of the body
-Hold tissues together
-Stretches and contracts positively
-Maintains mineral homeostasis
2A. Loose/Areolar
-Most abundant
-Collagenous
-Holds organs in place
-Attaches epithelial tissue to underlying tissues
2B. Dense Fibrous
-Fibers as main matrix element
-Ligaments
-Connects bones to bones
-Tendons
-Connects bones to muscles
2C. Adipose
-Fat storage for insulation and energy storage
-Under skin and around internal organs
2D. Blood
-Only fluid connective tissue
-Flows through blood vessels
-Carries oxygen, nutrients, hormones, and antibodies
2E. Cartilage
-Collagenous fibers embedded in chondroitin sulfate
-Cushion between bones
2F. Bone
-Hard
-Framework
3. Muscle Tissue
-Long cells (Muscle Fibers)
-Voluntary and Involuntary movement
3A. Skeletal
-Connected to bones
-Allows wide range of Voluntary movement
3B. Cardiac
-Thick middle layer of Heart
-Contracts and relaxes to produce heartbeats and circulate blood
-Involuntary
3C. Smooth
-Closely arranged cells forming sheets
-Propels substances along the internal passageway
-Walls of hollow organs
-Involuntary
4. Nervous Tissues
-Composed of nerve cells (neurons) and glial cells
-Function as support cells
-Transmits nerve impulses around the body
4A. Neurons
-Senses stimuli
-Transmits electrical signals
Lesson 4: Plant Cells and Plant Tissues
Plant
-Eukaryote
-Kingdom Plantae
-Photosynthetic
-Unlimited localized growth
-Cell walls are rigid because of cellulose
-No locomotor organs = Stationary
1. Guard Cells
- Found in leaves
- Surrounds and controls stomata (plant pores) in response to temp and water changes
- Come in pairs
2. Root Hairs
- Dermal tissue of roots
- Adds surface area to roots
- Increases absorptive capacity
3. Palisade/Leaf Cells
- Photosynthesis
- Contains chloroplasts which contains chlorophyll (green pigment that absorbs light)
Plant Tissues
1. Meristematic Tissue
- Continuously reproducing young cells through division
- Apices of roots and shoots
- Embedded in vascular tissues
- Increases girth of roots and stems
1A. Apical Meristem
- Tips of roots and shoots
- Primary growth (Height)
1B. Intercalary Meristem
- Between mature tissues of plant
- Base of leaves
- Longitudinal growth of plants
1C. Lateral Meristem
- Vascular tissues
- Thickness of plant
- Secondary growth (Width/Girth)
2. Permanent Tissue
- 2 Types (Simple & Complex)
2A. (Simple) Parenchyma
- Most abundant
- Large vacuoles
- Roots, stems, leaves, fruits
- Controls photosynthesis, respiration, protein synthesis
2B. (Simple) Collenchyma (Greek “Kolla” = Glue)
- Structure of plant tissues
- Shoots and leaves
- Flexibility
2C. (Simple) Sclerenchyma (Greek “Skleros” = Hard)
- Cellulose and Lignin Cell walls
- Matured dead cells
- Wooden part or stem
2D. (Complex) Vascular
- Nutrient and water transport
- Only found in vascular plants (Tracheophytes)
- Lignified tissues
- Xylem
- Water transport from roots to stem, leaves, and buds
- Phloem
Carbohydrate transport
2E. (Complex) Dermal
- Outer protective layer of plants
- Plant skin
- Epidermis
- Single layer of tightly packed cells
- Periderm
- AKA Bark
- Multi-layered
- Composed of cork cells, phelloderm, and cork cambium
