Hettema - Prokaryotes and Eukaryotes

Question 1

Define cytosol

Answer 1

The fluid present inside the cell

Question 2

Define cytoplasm

Answer 2

The organelles and cytosol found inside the cell, excluding the nucleus

Question 3

name 2 problems with eukaryotes being bigger than prokaryotes

Answer 3

eukaryote sa:v ratio is small

keeping the conc of reactants high is difficult

Question 4

name 2 methods of decreasing sa:v ratio in eukaryotes

Answer 4

flattening cells

microvilli

Question 5

what happens to the volume of a sphere when you increase the radius 3x

Answer 5

volume increases 27x

Question 6

how is the concentration of a cell maintained?

Answer 6

compartmentalisation

Question 7

which structures are found in the nucleus and nucleolus

Answer 7

nucleus: complexes of dna and proteins that are visible in the cell
nucleolus: granular body made up of RNA and protein
site of ribosomal RNA synthesis and ribosome subunit assembly

Question 8

describe the shape and purpose of endosomes

Answer 8

bound by single mem
shape varies
v important in sorting proteins for degradation or re-use

Question 9

describe the shape and purpose of lysosomes

Answer 9

bound by single mem
heterogeneous morphology
contains heterolytic enzymes for breakdown of polymers at low pH

Question 10

describe the shape and purpose of the smooth endoplasmic reticulum

Answer 10

no ribosomes on outer surface
lipid biosynthesis
modifying h phobic chemicals to make them H2O soluble

Question 11

describe the shape and purpose of rough endoplasmic reticulum

Answer 11

ribosomes on outer surface

synthesis of many proteins destined for secretion and membrane incorporation

Question 12

describe the shape and purpose of the golgi apparatus

Answer 12

stack of flattened vesicles
processing/packaging of secretory and membrane proteins
sotring proteins for various destinations in the cell
- vesicles of Golgi bud off fuse and reform to make new sheets

Question 13

describe the secretory pathway

Answer 13

starts at endoplasmic reticulum –> Golgi –> Secretory vesicles

Question 14

describe the endocytic pathway

Answer 14

starts at endosome –> lysosome –> autophagosome –> phagosome
(this is endocytosis)

Question 15

name 3 reasons why cells undergo endocytosis

Answer 15

uptake small macromolecules by invagination of plasma membrane (endocytosis)
uptake molecules from outside of the cell (phagocytosis)
degradation of aged organelles by lysosomes (autophagy)

Question 16

describe the shape and purpose of peroxisomes

Answer 16

single mem
small spheres
low abundance
frequently crystalline core (due to high conc of protein)
fatty acid oxidation (and other substrates) produce H2O2
catalyse degrades H2O2

Question 17

describe the shape and purpose of mitochondria

Answer 17

bean shaped
=< 25% cell volume
site of most respiration
endosymbiotic theory

Question 18

describe the shape and purpose of the vacuole

Answer 18

membrane bound organelle
storage of small molecules
lysosome-like activities
turgor pressure

Question 19

describe the shape and purpose of cell wall

Answer 19

extracellular
consists of cellulose microfibrils - rigid
plasmodesmata between neighboring cells
stops plant cell bursting

Question 20

describe the shape and purpose of the chloroplast

Answer 20

a plastid
have internal mem structure - thylakoids
contain own genome/ replication machinery/ribosomes
- endosymbiotic theory

Question 21

describe the shape and purpose of cytoskeleton

Answer 21

acts as skeleton and muscle
provides stability and movement
moves cell and cellular content
main cytoskeletal elements: intermediate filaments/microtubules/microfilaments