Textbook

Question 1

Define autocrine regulation

Answer 1

Cell function regulators that come from the cell itself

Question 2

Define paracrine regulation

Answer 2

Cell function regulators that come from nearby cells

Question 3

Define endocrine regulation

Answer 3

Cell function regulators that come from cells located far away and are delivered by the blood stream

Question 4

Define neurocrine regulation

Answer 4

Cell function regulators that come from nerve endings

Question 5

Describe the types of epithelial cells (not their arrangement)

Answer 5

Squamous: cells are flat
Cuboidal: cells square in section
Coloumnar: cells taller than wide

Question 6

Describe arrangements of epithelial cells

Answer 6

Simple: Single layer of cells
Stratified: several layers of cells
Pseudo-stratified: single layer of cells appearing to be stratified as nuclei are arranged at different heights

Question 7

Describe the types of anchoring junctions

Answer 7

Adherens junctions: bind actin networks together
Desmosomes: connect cytoskeleton filaments of adjacent epithelial cells
Hemidesmosomes: connect filament networks to extracellular matrix

Question 8

What membranes do epithelial cells have?

Answer 8

Apical membrane - facing outward

Basolateral membrane - facing inward

Question 9

Describe the kinds of junctions between epithelial cells

Answer 9

Tight junctions - adhere cells together near apical membranes, maintaining cell polarity
Anchoring junctions - helps resist tensile and shearing forces by binding cytoskeletal structures (3 types:adherens junctions, desmosomes and hemidesmosomes)
Gap junctions - mediate cell-cell communication as conducting pores align allowing selective diffusion.

Question 10

Describe the different types of anchoring junctions

Answer 10

Adherens junctions - bind actin networks together
Desmosomes - connect cytoskeletal filaments of adjacent cells
Hemidesmosomes - connect filament networks to extracellular matrix

Question 11

Explain the difference between absorptive and secretary epithelial cells

Answer 11

Absorptive - active sodium ion transport drives solute and water reabsorption

Secretary - Active chloride ion transport drives fluid secretion

Question 12

Explain the difference between tight and leaky epithelia

Answer 12

Tight - prevents significant movement of molecules between cells, located distally, withstand large osmotic gradients

Leaky - low resistance pathway for ions and water, form imperfect seals, located proximally in gi tract and kidneys

Question 13

What is the function of peroxisomes?

Answer 13

Contain enzymes involved in oxidative metabolism which use oxygen and produce hydrogen peroxide

Question 14

Describe microfilaments

Answer 14

• Made of actin

- Involved in cell movement

Question 15

Describe intermediate filaments

Answer 15

• Form alpha helixes

- Contribute to mechanical strength and stability

Question 16

Describe microtubules

Answer 16

• Hollow tubes

- Involved in chromosome separation during mitosis

Question 17

What is the name of the space between the inner and outer nuclear membrane?

Answer 17

Perinuclear space

Question 18

Explain semi conservative replication

Answer 18

Each daughter molecule contains 1 DNA strand from the parent molecule and 1 newly copied strand

Question 19

Define protein trafficking

Answer 19

The movement of a protein from its site of production to its target site

Question 20

Explain the mechanism of DNA repair

Answer 20

1) Enzymes recognise the damage
2) Endonucleases nick the strand
3) Exonucleases remove the incorrect bases
4) DNA polymerase fills the gap with the correct bases
5) DNA ligase joins the strands up

Question 21

Describe DNA replication on the lagging strand

Answer 21

Lagging strand is 3’-5’ so DNA polymerase can’t copy directly
Okazaki fragments each primed with RNA
5’-3’ RNase H removes RNA and DNA polymerase replaces it with DNA

Question 22

What must occur before a cell can occur?

Answer 22

1) Replication of chromosomes
2) Segregation of chromosomes into 2 diploid sets
3) Division of cytoplasm and cell membrane

Question 23

Describe the stages of mitosis

Answer 23

1) Prophase, chromosomes condense
2) Metaphase, chromosomes line up on equator of nuclear spindle
3) Anaphase, chromosomes pulled apart by spindle
4) Telophase, chromosomes in 2 clusters which will form daughter cell nuclei

Question 24

Define and explain the process of neoplasia

Answer 24

Neoplasia: the growth of a tumour
Loss of cell cycle checkpoints - accumulation of DNA damage - development of malignant characteristics - increased material through cell cycle - increased number of neoplastic cells : normal cells - tumour

Question 25

What causes a mosaic karyotype?

Answer 25

Mitotic non disjunction that occurs after the first division

Question 26

Define mosaicism

Answer 26

Presence of 2+ cell lines in an individual

Question 27

What does Ka equal?

Answer 27

Ka= amount of a drug required to occupy 50% of receptor population at equilibrium

Question 28

Explain the difference between efficacy and affinity

Answer 28

Affinity is how strongly a molecule binds to a receptor | Efficacy is the size of the response produced when a molecule binds to a receptor

Question 29

Define tachyphylaxis

Answer 29

Rapidly diminishing response to successive doses of a drug making it less effective

Question 30

Define codon

Answer 30

Three base pair sequence that codes for an amino acid

Question 31

Define point mutation

Answer 31

A change in a single nucleotide

Question 32

Define non sense mutation

Answer 32

Point mutation where amino acid is changed to a stop codon

Question 33

Define frameshift mutation

Answer 33

Mutation caused by addition/deletion of a base pair/s resulting in an unnatural reading frame from the position of the mutation to the end of the gene

Question 34

Define dynamic mutation

Answer 34

When nucleotide repeats expand generation by generation

Question 35

Why is an intron mutation unlikely to result in disease?

Answer 35

Because introns are spliced out during processing to mRNA

Question 36

Explain what a wobble base is

Answer 36

A wobble base is the base at the 3' end of a codon (and therefore the 5' end of an anticodon) that allows a tRNA molecule to recognise multiple codons

Question 37

What unusual recognition can occur in wobble bases?

Answer 37

G can recognise U (to form 3 H bonds) and I can recognise U, A and C (to form 2 H bonds)

Question 38

Explain the difference between Northern, Southern and Western blotting.

Answer 38

Northern - labelled antisense probes to assess size and quantity of mRNA in sample Southern - same method, but assessing DNA not mRNA Western - Assess protein in sample, using antibody to bind to protein, then another antibody to bind to antibody so colorimeter can be used

Question 39

What is a ganglion?

Answer 39

Where nerve cells synapse with each other, made up of neural cell bodies, glial cells and connective tissue.

Question 40

Explain the difference between pre and post ganglionic neurones.

Answer 40

Pre ganglionic = Neurones between signal cord and ganglia , cell body in the ganglia, only release Ach neurotransmitter Posts ganglionic = Neurones between ganglia and target tissue, cell body in target tissue, release many types of neurotransmitter

Question 41

What is the periosteum?

Answer 41

A membrane that covers the outer surface of all bones

Question 42

What is the endosteum?

Answer 42

A membrane that lines the inner surfaces of all bones

Question 43

What is osteoid?

Answer 43

The organic compound of bone

Question 44

What is the difference between osteoblasts, osteoclasts and osteocytes?

Answer 44

- Osteoblasts secrete osteoid for bone formation - Osteoclasts reabsorb bone - Osteocytes preserve bone matrix

Question 45

What is the difference between macrophages and neutrophils?

Answer 45

Neutrophils are short lived with a self destruct function after phagocytosis, macrophages do not

Question 46

What is the difference between non-sense and missense mutations?

Answer 46

Missense is substitution of one base for another, non sense of substitution for a stop codon