mock exam

Question 1

what is the structure of a protein?

Answer 1

polymer of amino acids
joined by peptide bonds
formed by condensation
primary structure in order of amino acids
secondary structure is folding of polypeptide chain due to hydrogen bonding
tertiary structure is 3D folding due to hydrogen bonds and ionic bonds

Question 2

what does the nucleus contain?

Answer 2

DNA

Question 3

what three components does the nucleus have?

Answer 3

nuclear envelope
nucleoplasm
nucleolus

Question 4

what does the nuclear envelope allow?

Answer 4

the passage of large molecules such as mRNA and ribosomes

Question 5

what does the nucleoplasm contain?

Answer 5

chromatin which condensed to chromosomes in cell division

Question 6

what are nucleolus?

Answer 6

in the nucleus, sites of formation of rRNA - consistent of ribosomes

Question 7

what is the function of mitochondrian?

Answer 7

produce ATP in aerobic respiration. some of these reactions are in the matrix or inner memebrane

Question 8

what is the mitochondria made up of?

Answer 8

two membranes folded in to from cristae

ribosomes so they can make their own proteins

Question 9

what is the rough endoplasmic reticulum

Answer 9

has ribosomes on outer surface and transports proteins made there.

Question 10

what does the smooth endoplasmic reticulum do

Answer 10

contains membranes that lack ribosomes , associated with synthesis and transport of lipids

Question 11

what are ribosomes important for?

Answer 11

protein synthesis as they are the site of translation where mRNA is used to assemble the polypeptide chain

Question 12

what are functions of the golgi body?

Answer 12

-secreting carbohydrates eg for the formation of plant cell walls
produces glycoprotein
transports and stores lipids
forms lysosomes containing digestive enzymes

Question 13

what are lysosomes?

Answer 13

small vacuoles and are formed by being pinched off from the golgi body

Question 14

what are centrioles?

Answer 14

located outside nucleus
2 rings of microtubules
together = centrosome

Question 15

what are vacuole?

Answer 15

contains cell sap - solution which stores glucose amino acids and minerals

Question 16

what functions does the cell wall have?

Answer 16

transport - gaps between cellulose fibres make cell wall fully permeable to water and dissolved molecules and ions

Question 17

what do lipids contain?

Answer 17

carbon hydrogen oxygen

Question 18

what are lipids…therefore?

Answer 18

non-polar compounds therefore are soluble in water but dissolve in organic solvents such as alcohols

Question 19

what are triglycerides made up of?

Answer 19

glycerol molecule and three fatty acids

Question 20

how do the fatty acids join in a triglycerides

Answer 20

condensation reaction

Question 21

what bonds are in triglycerides

Answer 21

ester bonds

Question 22

what is a phospholipid?

Answer 22

special type of lipid - 1 phosphate that is hydrophilic

2 fatty acids - hydrophobic

Question 23

what properties of lipids

Answer 23

if hydrocarbon chain has single carbon bonds = saturated

if carbon bonds aren’t one = unsaturated

Question 24

what are the roles of lipids - phospholipids?

Answer 24

• insulation of axons of nerve cells

Question 25

what are the roles of lipids - triglycerides?

Answer 25

energy reserves in both plants and animals thermal insulation fat - around delicate organs

Question 26

what is the test lipids?

Answer 26

mix ethanol and shake with water | positive = white emulsion

Question 27

what is water potential?

Answer 27

measure of free energy of water molecules and is the tendency for water to move

Question 28

what is water potential measured in?

Answer 28

kilopascals kPa

Question 29

what water potential does pure water have?

Answer 29

zero as it has no tendency to move

Question 30

what is it called when the water potential is only related to the concentration of the solution?

Answer 30

the solute potential 🌵

Question 31

what does the solute potential measure?

Answer 31

how easily water molecules move out of a solution , the more solute present the more tightly water molecules are held , so a higher concentration has a lower more negative solute potential

Question 32

what does the pressure potential mean?

Answer 32

a force which increases the tendency of water to move out making the cell turgid

Question 33

water potential of s cell =??

Answer 33

pressure potential + solute potential

Question 34

explain DNA replication?

Answer 34

chromosomes make copies of themselves so that when cells divide each daughter cells receives an exact copy of genetic cell

Question 35

when does this copying of the DNA take place?

Answer 35

takes place in nucleus during interphase

Question 36

what is conservative replication?

Answer 36

where the parental double helix remains intact and a whole new double helix is made

Question 37

what does semi conservative replication mean?

Answer 37

parental double helix separates into two strands

Question 38

what is dispersive replication?

Answer 38

when two double gloves contain fragments from both stands of parental double helix

Question 39

what does the enzyme helicase do?

Answer 39

unwinds DNA and bind nucleus acids and nuclei is acid protein complexes.

Question 40

what else do helixase do?

Answer 40

they separate double stranded DNA into single strands allowing each strand to be copied

Question 41

what are enzymes?

Answer 41

globular proteins that are catalysts

Question 42

what do enzymes do?

Answer 42

sped up reactions not used up not changed high turn over number

Question 43

what is enzyme inhibition?

Answer 43

the decr se in rate of an enzyme controlled action

Question 44

what is a competitive inhibitor?

Answer 44

has a molecular shape complementary to its active site like the substrate it therefore they compete for the active site

Question 45

what is a non competitive inhibitor?

Answer 45

they bind to enzymes at an allosteric site so they don’t need to compete with substrate therefore no enzyme substrate complexes form so enzymes denature

Question 46

what is the progress of an enzyme controlled reaction?

Answer 46

1 substrate enters active site and are held by weak bonds 2 substrates are converted to products and products are released 3 active site available for two new substrate molecules starts all over again

Question 47

what are the limiting factors for enzyme controlled reactions?

Answer 47

rate of an enzyme

Question 48

what are the limiting factors in enzyme?

Answer 48

concentration of substrate and enzyme , temperature and PH

Question 49

different enzymes have different...

Answer 49

optimum temperatures

Question 50

the rate of reaction can be increased by...?

Answer 50

adding more substrate because in a low substrate many active sites are empty the

Question 51

what happens when all active sites are occupied?

Answer 51

reaction rate rises

Question 52

what does an immobilised enzyme mean?

Answer 52

when enzymes are fixed or bound to s particular substance

Question 53

why are immobilised enzymes used in industry?

Answer 53

can easily be reused

Question 54

what does the order of units go?

Answer 54

M CM MM funny nm nm

Question 55

what are the numbers above

Answer 55

x 100 x 10 x1000 x1000

Question 56

what are nucleotide make up of

Answer 56

phosphate - circle sugar - hexagon base - rectangle

Question 57

what does ATP contain?

Answer 57

base adenine, sugar ribose and three phosphate groups

Question 58

what roles does ATP have?

Answer 58

- metabolic processes - build large molecules - active transport - movement - for muscle contraction

Question 59

what is DNA composed of?

Answer 59

two polynucleotides strands wound around eachother in a double helix

Question 60

what complementary base pairs are there?

Answer 60

adenine + thymine | guanine + cytosine