Suitable for AS and A2 Biology - basic physiology knowledge

1. Cells and their function – Mitosis – Meiosis – Tissues – Body
Cavities

2. What is
life?
Movement
Growth
Reproduction
Excretion Nutrition
Sensitive/Responsive
Respiration
MRS
NERG

3. Cell membrane
Nucleus
Cytoplasm
Centrioles
Mitochondria
Lysosomes
Golgi apparatus
Rough endoplasmic reticulum
Smooth endoplasmic reticulum
Ribosomes

4. The cell membrane (also known as plasma membrane) is composed of a phospholipid bilayer which
separates the cell from its surrounding environment. On the surface of the cell membrane are
carbohydrate polymers which form glycoproteins and glycolipids. They help with cell recognition and are
involved in cell signalling.
The cell membrane is selectively permeable:
 It contains pores so only small molecules can pass through
 It has carrier proteins for facilitated diffusion of substances such as glucose
 Substances can enter via active transport – the energy required this is supplied by ATP, the cells
‘energy currency’. Sodium enters this way
 It has carrier proteins so large molecules and molecules which are too hydrophilic can pass through
 Cholesterol for stability
Function:
 Controls what enters and exits the cell

6. Cytoplasm
This is the aqueous material found within the cell and contains the nucleus, organelles and dissolved
solutes (e.g. glucose, ions, ATP)
Function:
 Provides the cell with support
Nucleus (largest organelle)
This is the information centre of the cell – it contains chromosomes which consist of the heredity
material, DNA, which has the information for protein synthesis and tells the cell how to function.
It is surrounded by a nuclear envelope; a double membrane which restricts the passage of molecules
(there are openings, however, called cannuli)

7. The mitochondria are the powerhouse of the cell.
This is the site of cellular respiration (chemically burn glucose to make energy).
The outer membrane is smooth whilst the inner membrane is highly folded to increase the surface area
for ATP production to take place. The energy itself is stored in the bond that connects the phosphate
group to the rest of the molecule. If one of the phosphate groups is ‘snapped off’, the bond is broken
and energy is released. The remaining molecule is ADP. The cell re-attaches to another phosphate group
during its metabolic processes so energy is stored once more as ATP.
ATP <-> ADP + Energy
N.B. Mitochondria possess their own DNA so replicate
independently.

8. Name of Organelle Appearance Function
Ribosomes Spherical. Can float free or are
associated to the endoplasmic
reticulum
Protein synthesis
Lysosomes Membrane bound sacs Contain digestive enzymes to digest
material taken in by the cell during
endocytosis or phagocytosis. Destroy
worn out organelles and sometimes
the cell itself
Golgi Apparatus/Body Stack of flattened sacs Modifies cell products and packages
them into vesicles. Involved in
formation of lysosomes

9. Appearance Function
Smooth E.R No ribosomes attached to
the surface
Synthesis and transport of
lipids and steroids
Rough E.R Ribosomes attached to the
surface
Synthesis and transport of
proteins

10. The centrioles are rod-like structures found in centrosomes (lie at right angles to each
other) and are responsible for spindle formation during cell division.
Nerve cells do not have a centrioles therefore do not divide.

11. 1. A small particle is present outside the cell
2. The cell membrane invaginates and starts to enclose
the particle
3. The cell membrane completely surrounds the particle
and seals it in a vesicle
4. The vesicle detaches from the membrane and enters
the cell
5. A lysosome fuses with the phagocytic vesicle containing
the particle and destroys it

12. The cells of the body are classified into two types…
Somatic Germ
Which cells? All the cells in the body
except those involved in
reproduction
Ova and Spermatozoa
How do they divide? Mitosis Meiosis

13. Mitosis creates two identical diploid daughter cells.
It is also involved in growth and repair
5 main phases… It Pays More At Tesco's
1. Interphase
2. Prophase
3. Metaphase
4. Anaphase
5. Telophase

14. INTERPHASE • Replication of DNA
• Forms new organelles
• Build up energy stores
PROPHASE • Chromosomes contract and become shorter
• Chromatids (identical pair of chromosomes)
held together at the centromere
• Centrioles at opposite ends of the poles and
spindle formation starts
• Nuclear membrane breaks down
METAPHASE • Chromosomes migrate to the equator and ttach
to the spindle fibres
• Sister chromatids orientate themselves towards
the poles
ANAPHASE • Sister chromatids pulled towards opposite ends
of the poles _ this requires lots of ATP
TELOPHASE • Chromatids reach poles
• The cell splits (cytokinesis) to produce two
identical cells
• Spindle breaks down
• Nuclear membrane reforms
• Chromatids unwind

15. Meiosis is the creation of four haploid non-identical gamete cells. It occurs over the
course of two successive divisions; meiosis 1 and meiosis 2.
1. Interphase
2. Prophase
3. Metaphase
4. Anaphase
5. Telophase
______________________________
1. Prophase
2. Metaphase
3. Anaphase
4. Telophase
5. Interphase

16. Prophase Metaphase Anaphase Telophase
Meiosis 1 • Nucleolus
disappears
• Homologous
chromosomes form
a bivalent
• The bivalents cross
over (genetic
exchange at the
chiasmata – new
combination of
alleles)
• Chromosomes
condense
• Bivalents line up
at the equator and
spindles attach to
the centromeres
• Independent
assortment
• Bivalents pulled
apart – one
chromosome goes
to each pole
• Chromosome
reaches pole
• Cytokinesis
Meiosis 2 • New spindle
formation at right
angle to first
• Chromosomes
move to equator
and chromatids
orientate towards
• Chromatids
separate
• Chromatids reach
poles – cytokinesis
• Nucleolus
reappears

17. Meiosis leads to genetic variation. This is achieved through crossing over, independent assortment and
because meiosis halves the number of chromosomes.
Mitosis Meiosis
Maintains chromosome number Halves chromosome number
One division Two divisions
2 daughter nuclei 4 daughter nuclei
No crossing over or independent
assortment
Crossing over and independent
assortment
Genetically identical daughter cells Non-identical daughter cells

18. TYPES
OF
TISSUE
Muscle
Nervous
Connective
Epithelial

19. Epithelial tissue is one of the simplest forms of tissue and covers both the inner and outer surface of the
body (e.g. skin, organs, blood vessels)
Can be simple (one cell thick) or complex (stratified, more than one cell thick)
Functions of Simple Epithelial Tissue
 Protection  e.g. of organs from microbial invasion, mechanical injury, dehydration
 Absorption  provides a barrier to help/hinder movement of material
 Sensation  most nerve endings terminate in epithelium
 Secretion  specialised cells produce a discharge (glands)
 Excretion  removing material from the body e.g. specialised cells in the kidney
 Surface transport  e.g. cilia beat rhythmically to sweep material along
Functions of Complex Epithelial Tissue (stratified transitional, stratified epithelium)
 Forms a tough impervious barrier

20. Squamous
Cuboidal
ColumnaCiliated
Pseudostratified
Stratified
Epithelial
Stratified
Transitional

22. Connective tissue consists of cells embedded in an extracellular matrix or ground substance.
It is responsible for supporting and holding other tissues and organs in place. It also provides the
transport system for the body – transporting the nutrients to target tissues and waste products away.
Loose Connective Tissue  Areolar and Adipose
Dense Connective Tissue  Tendons and Ligaments

23. Areolar Tissue Adipose Tissue
Found all over the body…
• Wrapped around organs
• Packing material between tissues
• Connects skin and structures
Scattered throughout areolar tissue are collagen fibres
and elastin…
Collagen fibres  form numerous wave bundles.
Flexible, strong
Elastin  flexible and elastic
Together provide tensile strength and resilience
Also known as fatty tissue due to containing numerous
closely packed fat cells
Functions…
• Energy store
• Insulation
• Protection

24. This type of tissue contains more fibres than cells. There are 2 types:- irregular (randomly arranged) and
regular (orientated to run parallel)
White Fibrous Yellow Dense Cartilage
• Tough and shiny
• Numerous bundles of regular
collagen
• Strong, flexible, inelastic
• Found in tendons
• A loose network of irregularly
arranged branched yellow fibres
• Flexible, elastic, strong
• Found in ligaments, walls of
arteries, cords in the neck
• Has a matrix called a chrondrin
• Strong, resilient and flexible
• Has no blood supply so is fed by
perichondrium covering its surface
• 3 types of cartilage…
1. Hyaline (articular surfaces)
2. Elastic (pinna, epiglottis)
3. Fibrocartilage (intervertebral
discs)

25. The body is divided into three distinct cavities…
 Thoracic
 Abdominal
 Pelvic
All cavities are lined with a serosal
membrane
Serosal membranes apposing boundary
of cavity = parietal
Serosal membranes apposing boundary
of organs within cavity = visceral

26.  Thoracic Cavity
Contains the heart, lungs and other associated structures. Divided into right and left pleural cavities by
a double layer of pleura called the mediastinum. The mediastinum contains pericardial cavity
surrounding the heart. Each pleural cavity contains a lung and a small amount of pleural fluid
 Abdominal Cavity
Contains the organs of the digestive system and related glands, the urogenital system and all the
associated nerves and vessels that supply these systems. The internal surface of the abdominal cavity is
lined with a serous membrane called the peritoneum. The peritoneum forms a continuous sheet forming
a closed cavity (peritoneal cavity – N.B. only contains a little peritoneal fluid, no organs)
 Pelvic Cavity
Contains the urinary bladder, the rectum and the reproductive organs. The walls of the cavity are
formed by muscles and ligaments