cell structure

Question 1

Name 5 properties of the cell membrane briefly

Answer 1

separate interior + exterior
has phospholipid bilayer
used in cellular processes
attachment surface for cell wall
selectively permeable to ions + organic molecules

Question 2

what molecules can and cannot cross the cell membrane

Answer 2

charged ions + glucose CAN’T CROSS

O2 + CO2 + H20 + NO can cross by diffusion

Question 3

what does the phospholipid bilayer consist of

Answer 3

hydrophilic outer heads = polar
hydrophobic fatty acid tails - inner core = non polar
embedded proteins

Question 4

what cellular processes is the cell membrane used for

Answer 4

cell adhesion
ion conductivity
signalling

Question 5

why can’t charged ions pass through the membrane

Answer 5

can’t pass through hydrophobic regions ( not through inner core)
so can’t pass through core of phospholipid bilayer

Question 6

why is the membrane called fluid mosaic

Answer 6

fluid = components move around
mosaic = variety of lipids + proteins --> can form complexes

Question 7

what does the mother centriole do in a centrosome

Answer 7

older one in pair

helps making cilia + flagella

Question 8

how does the centrosome make the mitotic spindle

Answer 8

centrosome nucleated tubules interact with chromosome

builds spindle

Question 9

how are centrosomes used in prophase

Answer 9

associated with nuclear membrane

Question 10

what are 3 properties of lysosome

Answer 10

contain hydrolytic enzymes + digest cellular components
used with macrophages
contain 50+ diff enzymes active at pH 5

Question 11

what is cytosol + its function

Answer 11

intracellular fluid where organelles held

separated into compartments by membranes

Question 12

what is a vacuole

Answer 12

closed compartment contain organic + inorganic molecules + enzymes in solution
formed by fusion of multiple membrane vesicles

Question 13

describe 4 functions of the vacuole

Answer 13

role in autophagy
aid in lysis + forming vesicles
helps maintain balance between biogenesis + degradation of cell structures

Question 14

what is autophagy

Answer 14

vacuole helps to break down proteins in cell + prevents build up of misfolded proteins
beta amyloid —> Alzheimers

Question 15

what are the main functions of mitochondria

Answer 15

ATP synthesis for: antibodies, enzymes, hormones –> using ribosomes to make proteins
ATP to regulate cell metabolism (need for ion channels in membrane)
can be specific –> detoxify ammonia in liver
sensitive to hormones = oestrogen receptors

Question 16

what are extra functions of mitochondria

Answer 16

regulate apoptosis
Ca2+ signalling
cell metabolism
steroid synthesis 
cell membrane potential

Question 17

what does cytoskeleton contain

Answer 17

microfilaments made of actin protein
microtubules = tubular protein
intermediate filaments
dynamic structure

Question 18

what is the structure of golgi

Answer 18

flat tubes connected to ER

transports vesicles around

Question 19

what are the functions of Golgi apparatus

Answer 19

synthesises macromolecules
modify, sort + packages macromolecules for exocytosis/used in cell
carb synthesis
modify + complete synthesis of complex lipids + proteins (glyco lipids + proteins)
modifies proteins from ER + transport lipids around cell

Question 20

describe the structure of RER

Answer 20

network of continuous channel membrane
inner + outer surfaces
inner portion = exterior
ribosomes attached to exterior

Question 21

what are the functions of RER

Answer 21

makes lysosome enzymes + secretes proteins (glycosalyation)

makes integral membrane proteins that are embedded in membrane (ion channels)

Question 22

what is glycosalyation

Answer 22

adding carb chains to proteins – adds stability + allows tracking of molecules in cell signalling

Question 23

what is the structure of SER

Answer 23

network of continuous channel membrane
inner + outer surfaces
inner portion = exterior

Question 24

what is the main function of SER

Answer 24

phospholipid, steroid, lipid synthesis

Question 25

what areas secrete lipids, phospholipid + steroids + what's special about these areas

Answer 25

ovaries, testes, oil glands | they have loads of SER

Question 26

what does SER do in muscles

Answer 26

regulate Ca2+ conc in muscle cells

Question 27

what are other functions of SER

Answer 27

steroid + carbs, drug detox, | by attaching onto cell membrane

Question 28

how are vesicles used by cell for organising substances

Answer 28

separated from cytosol | so inside vesicle diff to cytosol env

Question 29

what are the functions of vesicles

Answer 29

``` transport metabolism buoyancy control enzyme storage chemical reaction chambers ```

Question 30

what is function of ribosomes

Answer 30

makes proteins

Question 31

how are proteins made at ribosome

Answer 31

mRNA transcribed copy from DNA tRNA - amino acid adapter one end matches mRNA code matches with specific amino acid

Question 32

how does nucleus control cell activities

Answer 32

maintains gene activity | regulate gene expression

Question 33

what is formed in the nucleus and how is DNA packaged

Answer 33

tRNA, mRNA, ribosomes formed | DNA packaged into chromatin

Question 34

why does the nucleus need nuclear pores

Answer 34

impermeable to large molecules

Question 35

what are histone proteins used for in the nucleus

Answer 35

they compress DNA so can fit inside cell

Question 36

what is nucleolus made of

Answer 36

proteins + RNA

Question 37

what is the main function of nucleolus

Answer 37

transcribe + modify rRNA + integrate ribosomal proteins --> immature proteins

Question 38

how is RNA synthesis regulated in the nucleolus

Answer 38

stress sensor based on cellular env

Question 39

what is function of peroxisomes

Answer 39

catalyse breakdown of toxic substances (H2O2) | clean up H2O2 in water + lipid metabolism

Question 40

what are the characteristics of prokaryotes

Answer 40

``` flagella protective capsules + sometimes mesosomes 70s ribosomes peptidoglycan cell wall nucleoid no Golgi apparatus no membrane bound organelles 1 plasmid - no true chromosomes ```

Question 41

what colour is gram positive

Answer 41

purple

Question 42

what is the shape of cell and cell wall if it is gram positive + colour

Answer 42

puprple rod shaped thick cell wall

Question 43

what are the characteristics of the cell of gram positive

Answer 43

thick cell wall - dye doesn't wash out easily + mesh for strength --> otherwise sensitive to osmotic changes + spherical shaped single cell membrane lots peptidoglycan - single cell membrane destroyed by steaming Not boiling rod shaped = spore forming

Question 44

what colour is bacteria that is gram negative

Answer 44

pink/red

Question 45

what is the shape of cell and cell wall if it is negative + colour

Answer 45

complex + thin peptidoglycan cell wall pink/redish complex wall --> dye diffuses out easily

Question 46

what is gram negative cell wall specially made of and why does it help

Answer 46

lipopolysaccharides: structural integrity resist chemical attack

Question 47

how do antibiotics cause cell lysis of bacteria

Answer 47

antibiotics alters peptidoglycan synthesis for cell wall --> cell wall can't form --> cell lysis

Question 48

what is function of microscopes + what is the function

Answer 48

can image single molecules within cells | point spread function allows sharper image