Cells

Question 1

Endogenous origin of eukaryotic compartments

Answer 1

Invagination of plasma membrane - then RER and nucleus formed

Question 2

Exogenous origin of eukaryotic compartments

Answer 2

cell encases another cell, this forms mitochondria

Question 3

Eukaryote origin - Archezoa hypothesis

Answer 3

phase 1 - invagination of membrane leads to first set of organelles
phase 2 - phagocytosis - one group of bacteria ingested which then forms mitochondria

Question 4

Meanings of exogenous and endogenous origins

Answer 4

endogenous = nucleus and RER formed 
exogenous = mitochondria and plastids formed

Question 5

function of plasma membrane

Answer 5

encloses cell content and separates it from the external environment
allows different concentrations of substances to be maintained

Question 6

function of lipid bilayer

Answer 6

communication w environment and diff cells
barrier functions to pass molecules in and out
cell growth, movement, division

Question 7

membrane fluidity

Answer 7

transporter/ enzyme activity regulated by fluidity
membrane can be adjusted to environment
lipid composition and temperature influence fluidity

Question 8

function of transporter proteins

Answer 8

move nutrients/ions across membranes

Question 9

function of linker proteins

Answer 9

join membranes to macromolecules

Question 10

function of receptors

Answer 10

transduce signals from environment

Question 11

function of membrane enzymes

Answer 11

catalyse reactions at membrane surfaces

Question 12

ampiphilic meaning

Answer 12

both hydrophobic and hydrophilic regions present

Question 13

glycosylated meaning and function

Answer 13

glycoproteins and glycolipids form a cell coat called the glycocalyx which prevents cell damage

Question 14

4 glycocalyx functions

Answer 14

protection, adhesion, recognition, storage

Question 15

3 types of active transport used to transport molecules across membrane

Answer 15

coupled, ATP driven, light/redox

Question 16

3 types of intracellular transport and meaning

Answer 16

Gated - through nuclear pores
transmembrane - across membranes
vesicular - via vesicles

Question 17

proteins made by ribosomes and sorted by signals

Answer 17

• nuclear localisation signal
• mitochondrial signal sequence
• vesicles travel from RER to other compartments

Question 18

sorting proteins to RER

Answer 18

• protein synthesis in cytosol
• proteins contain N terminal signal sequence
• signal sequence binds receptor on RER
• ribosome associates with RER
• polypeptide synthesis completed on RER
• protein translocates into RER membrane during synthesis
• signal peptide cleaved

Question 19

protein glycosylated

Answer 19

N = asparagine
O = serine, threonine

Question 20

3 different vesicular transport pathways

Answer 20

secretory, endocytic, retrieval

Question 21

Autophagy

Answer 21

Induction: organelles free
Closure: Autophagosome formed containing organelles
Autophagosome fuses with lysosome
lysosome digests what it contains