MTM WK3 - CELL PROCESSES

Question 1

STAGES OF CELL DIFFERENTIATION

Answer 1

stem cell gets signal & changes pattern on gene expression to reduce number of genes expressed
stem cells -> progenitors -> differentiated cell

Question 2

CELL POTENCY

Answer 2

• pluripotent (e.g. stem)
• multipotent (e.g. progenitor)
• unipotent (e.g. blood cell)

Question 3

PROTEIN SYNTHESIS (transcription translation)

Answer 3

in nucleus, 2 DNA strands separate & free nucleotides join to form mRNA & then in ribosome, translation happens & anti-codon on each tRNA binds to first codon (each tRNA comes with amino acid)

Question 4

RNA POLYMERASE location & job

Answer 4

• in gene promoter region (sits waiting for transcription)

- breaks up DNA to 2 strands so free RNA nucleotides can bind

Question 5

PARTS OF A TRANSCRIPTIONAL FACTOR

Answer 5

• DNA BINDING DOMAIN (binds to specific DNA sequence in promoter region)
• ACTIVATION DOMAIN (binds to RNA polymerase)

Question 6

WHAT ARE TRANSCRIPTIONAL FACTORS

Answer 6

proteins that bind to specific region of gene & express it (control gene expression)

Question 7

ERYTHROPOIETIN (EPO) CYCLE (when we need to make blood) (cascade cycle)

Answer 7

low O2 in PT = EPO released = activates TF which express genes which activates proteins that make proteins needed for RBC = RBC progenitor release = differentiate into RBC

Question 8

STRUCTURE OF CONNECTIVE TISSUE

Answer 8

special cells & an extracellular matrix (made of fibres e.g. collagen & ground substances)

Question 9

PROPERTIES OF CONNECTIVE TISSUE

Answer 9

• TENSILE STRENGTH (to resist pulling, stretching & tearing (made of collagen))
• ELASTICITY (to aid return to original shape after distortion (made of elastin))

Question 10

CELLS OF CONNECTIVE TISSUE (7)

Answer 10

• fibroblast - cigar nucleus, make fibres
• myofibroblast - used for repair
• plasma cell - circle nucleus, make antibodies
• adipocyte - nucleus pushed to one side, looks empty as staining process breaks fat in it (W = store fat for energy release, B = heat genesis)
• macrophage - phagocytic
• fibrocyte - fibroblast after it has released fibres
• mast cells - make histamine for inflammation

Question 11

FIBRES IN CONNECTIVE TISSUE (WHAT FIBROBLASTS MAKE)

Answer 11

• collagen - for tensile strength, tough, in tendon
• elastic - made of elastin & fibrillin (from FB), allow stretching (in lung, artery)
• reticular - made of reticulin, delicate framework of organs e.g. liver/spleen

Question 12

GROUND SUBSTANCE

Answer 12

• hyaluronic acid backbone with proteoglycans (hydrophobic AF) attached by link proteins
• below basal membrane between fibres and cells (to trap water)

Question 13

TYPES OF CONNECTIVE TISSUE

Answer 13

Loose, dense, adipose tissue

Question 14

LOOSE CONNECTIVE

Answer 14

• bind structures together (surround blood vessels)
• in basement membrane of epithelium
• site of metabolic exchange between capillary & tissue it supplies
• few fibres/fibroblasts more ground substance

Question 15

DENSE CONNECTIVE TISSUE

Answer 15

• provides tough physical support & protection
• less ground tissue than usual
• regular dense = fibres in one direction e.g. tendons
• irregular dense = fibres in opp. directions e.g. dermis

Question 16

ADIPOSE TISSUE

Answer 16

• adipocytes closely packed

- store lipids, surround/protect internal organs, insulating layer under skin

Question 17

MARFAN SYNDROME

Answer 17

• mutation in fibrillin gene = less stretchy tissue = risk of aortic aneurysms

Question 18

EHLER-DANLOS SYNDROME

Answer 18

abnormal collagen production = hypermobile joints

Question 19

LIPOMA

Answer 19

swelling of adipose tissue

Question 20

EDEMA

Answer 20

excessive accumulation of fluid in tissue sacs (pitting edema - press on swelling & stays)

Question 21

TYPES OF COLLAGEN

Answer 21

• 1 = tendon, ligament, bone
• 2 = surface of bone
• 3 = bone marrow
• 4 = basement membrane