Week 2 – Cells and Tissues

Question 1

What are primary and secondary active transport systems?

Answer 1

1. Primary uses ATP eg Na K pumps
2. Secondary - does not, as Na diffuses back across membrane it takes glucose with it

Question 2

What are endocytosis and exocytosis?

Answer 2

Vesicular transport of substances into and out of cells
Endocytosis - into
Exocytosis - out of eg waste

Question 3

How is resting membrane potential established and maintained?

Answer 3

• Voltage difference on either side of the cell membrane
• Largely determined by K, ∵ at rest, the membrane is much more permeable to K than Na.
• Active transport of sodium and potassium ions by the NaK pump maintains the Na & K concentration gradients

Question 4

What are mitosis and meiosis?

Answer 4

Mitosis - cell replication required for growth
Meiosis - production of reproductive cells

Question 5

Outline the lifecyle of a cell

Answer 5

Before replication, one chromosome is composed of one DNA molecule.
In replication (mitosis), the DNA molecule is copied (interphase), and the two molecules are known as chromatids.
Prophase - chromatids condense
Metaphase - chromatid pairs align in the ctr of the cell
Anaphase - chromatid pairs are split into chromosomes
Telophase - chromatids decondense and develop nuclear envelopes
If two identical daughter cells emerge - cytokinesis

Question 6

What’s the difference between Apoptosis and Necrosis?

Answer 6

Apoptosis
Cells dying naturally to maintain a balance of cellular multiplication
Removing unneeded cells during foetal development
Elimination of potentially dangerous cells eg cancer cells
Necrosis
Cellular death when cells are exposed to extreme conditions (heat, acid, toxins) damaging internal cell environment, leading to inability to perform fn & → death

Question 7

What is epithelial tissue?

Answer 7

• forms boundaries b/w different environments
• protects, secretes absorbs and filters
• skin surface, lining of digestive tract

Question 8

What is connective tissue?

Answer 8

supports, protects, binds other tissues together
* 1. loose
* 1. dense (contains more fibre)
* 1. cartilage

Question 9

What does muscle tissue do?

Answer 9

Contracts to cause movement

1. skeletal
2. cardiac
3. and smooth

Question 10

What does nervous tissue do?

Answer 10

responsible for internal communication
brain, spinal cord and nerves

Question 11

What are the different types of epithelium?

Answer 11

Simple
squamous
cuboidal
columnar
Stratified
squamous
cuboidal
columnar
pseuostratified columnar
Other
transitional
glandular

Question 12

How do epithelial tissues repair?

Answer 12

1. Initiated by trauma
2. Inflammatory chemicals make blood vessels leaky → WBC & clotting proteins
3. Clot replaced by granular tissue which is then replaced by surface epithelial tissue, which thickens and generates scar tissue
4. Fibroblasts bridge the gap, mature and pull the margins of the wound together
5. Macrophages phagocytise dead and dying cells and other debris