Cell structure + function

Question 1

Describe the role of the phospholipid bilayer

Answer 1

• regulating exchange in cells
• cellular communication
• structural support

Question 2

Describe the 2 components of the cytoplasm

Answer 2

Cytosol = fluid component
-> where chem reactions take place
Organelles = specialised structures which perform specific functions for normal cell homeostasis

Question 3

Describe + define receptors on the PM

Answer 3

• integral membrane proteins
• proteins on inside/surface of cell which receive a signal + cause a response
  -> proteins which react w/ ligands (molecules) to cause a biological response within the cell

Question 4

List the 4 types of receptors

Answer 4

• ion channels
• G protein-coupled receptors
• Transmembrane receptors w/ linked enzymatic domains
• intracellular receptors

Question 5

Describe the function of ion channels

Answer 5

Regulate movement of ions across a channel eg. nicotinic receptor activation
-> regulates events relying on an action potential

Question 6

Describe the function of G protein-coupled receptors

Answer 6

Receptors that cross the membrane / have 7 transmembrane domains
- activation of GPCR causes activation of nearby G protein which then regulates further signalling events + changes in cell function (intracellular)

Question 7

Describe the function of transmembrane receptors w/ linked enzymatic domains

Answer 7

Activates intracellular enzymatic domain when ligands bind to the receptor
-> slow effects eg. RTK’s -> insulin receptor

Question 8

Define ligand

Answer 8

A chemical messenger that acts as a signal to produce a change in the cell

Question 9

Describe the function of intracellular receptors

Answer 9

Alters production of proteins (transcription)
-> happens when a ligand binds to a receptor resulting in the molecule-receptor complex binding to DNA

Question 10

Describe the functions of the cytoskeleton + what it is composed of

Answer 10

• provides structural framework for the cell
• movement of cellular structures + materials
  Made of microtubules, intermediate filaments + microfilaments (tubulin, keratin + actin)

Question 11

Describe microvilli

Answer 11

• membrane extensions containing microfilaments
• increase SA for absorption of extracellular materials

Question 12

Describe cilia

Answer 12

• long extensions of PM containing microtubules
• acts as sensor/can move materials over cells surface

Question 13

Describe the function of the nucleolus

Answer 13

Synthesis + assembly of ribosomes

Question 14

Describe the function of the rough endoplasmic reticulum

Answer 14

• lipids + protein synthesis
• folds polypeptides into proteins
• packages newly synthesised proteins

Question 15

Describe the function of the smooth endoplasmic reticulum

Answer 15

• makes lipids + steroid hormones
• detoxifies drugs + alcohol

Question 16

Describe the function of proteosomes

Answer 16

Contain proteases which breakdown + recycle normal intracellular proteins
-> proteins tagged w/ molecule ubiquitin which signals for protein to be removed from cell

Question 17

Describe the function of mitochondria

Answer 17

Makes ATP
-> cristae contains important metabolic enzymes

Question 18

Describe the structure + function of fibroblast

Answer 18

Connective tissue cells involved in connecting body parts
-> produce collagen
-> contains high numbers of RER, ribosomes + golgi apparatus for production + secretion of collagen

Question 19

Describe the structure + function of macrophages

Answer 19

Cells that engulf bacteria
-> degrade bacteria therefore contain many lysozymes

Question 20

Describe the structure + function of neurons

Answer 20

Cells involved in the processing + communication of info in the NS
-> produce sig. amount of protein therefore many nucleoli

Question 21

Describe the structure + function of skeletal muscle fibres

Answer 21

• moves bone
• needs increased energy therefore contains many mitochondria

Question 22

Liver cell

Answer 22

contains increased smooth ER to produce bile (lipids)