Advanced Higher Biology Prelim Revision Flashcards Preview

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Flashcards in Advanced Higher Biology Prelim Revision Deck (96)
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1
Q

what is SDS- PAGE

A

separation of proteins by size alone

2
Q

how does SDS-PAGE separate proteins

A

by giving all molecules an equally negative charge and denaturing them

3
Q

what is western blotting

A

this is an analytical technique used after SDS-PAGE

4
Q

what is involved in western blotting

A

the gel is run and then the separated proteins are transferred onto a solid medium.

5
Q

how are proteins identified using western blotting

A

using specific antibodies that have reporter enzymes attached

6
Q

what is bright filed microscopy

A

used to observer:

  • whole organisms
  • parts of organisms
  • thin sections of dissected tissue
  • individual cells
7
Q

what is a haemocytometer

A

a graduated microscope slide that can be used to estimate cell numbers in a liquid culture

8
Q

what must be present in a cell culture

A

growth factors and nutrients

9
Q

what are growth factors

A

protein which promote cell growth or proliferation

10
Q

what is a colorimeter

A

used to measure the concentration of a pigment in a solution

11
Q

what is the proteome

A

the number of proteins expressed by a genome

12
Q

why is the number of proteins expressed higher than the number of genes expressed

A

due to alternative RNA splicing producing multiple proteins expressed by a single gene

13
Q

where are all protein synthesised

A

in the cystolic ribosome

14
Q

where are transmembrane protein synthesis completed

A

not completed in the cystol instead they carry a signal sequence which halts translation and directs the ribosome to doc with the endoplasmic reticulum

15
Q

what is the signal sequence on the transmembrane protein

A

short stretch of amino acids at the end of the polypeptide which determines the eventual location of the protein

16
Q

Describe the movement of proteins between membranes

A
  • proteins enter the membrane of the ER and are then transported by vesicles that bud off from the ER and fuse with the Golgi apparatus
  • as proteins move through the Golgi apparatus they undergo post-translation modifications
  • molecules move through the Golgi discs in vesicles
  • vesicles that leave the Golgi then take proteins to the plasma membrane
17
Q

what are the post-translational modification in the Golgi

A

addition of a carbohydrate molecule

18
Q

what is the quaternary structure

A

exists in proteins with several connected polypeptide subunits which are linked by bonds between the R -groups of the chain

19
Q

what are the 4 main amino acid classes

A

acidic - COOH carboxylic acid
basic - NH2 amine group
polar - OH hydroxide group
hydrophobic - CH hydrocarbon

20
Q

What is a peptide bond

A

joins two amino acids together to create a polypeptide chain

21
Q

how is a polypeptide chain formed

A

a condensation reaction

22
Q

what is a ligand

A

a substance which can bind to a protein

23
Q

what happens when the ligand binds

A

there is a conformational change which causes a change in the function of the protein

24
Q

what is a modulator

A

binds to the allosteric site of an enzyme altering the affinity of the active site for a substrate

25
Q

what are the two types of modulator

A

positive - increased affinity for substrate

negative - decreases affinity for substrate

26
Q

what is facilitated diffusion

A

is passive transport of molecules through transmembrane proteins form a high to low concentration

27
Q

what molecules pass through the plasma membrane by diffusion

A

oxygen and carbon dioxide

28
Q

describe the sodium potassium pump

A
  • pump has high affinity for sodium ions inside the cell
  • binding of 3 sodium ions occurs and pump is phosphorylated by ATP
  • conformation of protein changes and affinity for sodium decreases so sodium is pumped of the cell
  • 2 potassium ions bind outside the cell
  • pump is dephosphorylated and affinity for sodium decreases
  • potassium is then pumped inside the cell
29
Q

what molecule are transported by hydrophobic signalling

A

steroid hormones such as oestrogen and testosterone

30
Q

describe hydrophobic signalling

A
  • steroid hormone passes across the plasma membrane
  • the steroid hormone then attaches to hormone receptor complex, activating it
  • the hormone receptor complex then binds to section of DNA called hormone response element which influence the rate of transcription
31
Q

what molecules are transported by hydrophilic signalling

A

hormones such as insulin and neurotransmitters

32
Q

Describe hydrophilic signalling

A
  • transmembrane receptor changes conformation when ligand binds
  • signal is then transduced across the membrane by converting extracellular binding event ton signal
  • Transducin then involves either G-protein relay or Phosphorylation cascade
33
Q

what is G-protein relay

A

G-protein relays signal form activated receptor to target proteins

34
Q

what is phosphorylation cascade

A

involves series of events with one kinase enzyme activating the next and so on

35
Q

describe the process of nerve impulse transmission

A
  • The neurotransmitter binds to a receptor causing a conformational change.
  • this conformations change leads to the opening of ligand gated sodium channel
  • the threshold is reached triggering the opening of voltage gated sodium channel be opened. this is depolarisation
  • the maximum potential is reached and channel closes, triggering opening of potassium gated channel to open
  • potassium ions flood into the cell causing repolarisation
  • threshold is reached and channel closes
  • sodium potassium pump works to restore the resting potential
36
Q

what is the charge of neuron when sodium floods out of cell

A

becomes more positive

37
Q

what is charge of neuron when potassium floods into cell

A

more negative

38
Q

what is charge of resting potential

A

more negative

39
Q

what are the two photoreceptors in the eye and what is their purpose

A

rod cells - function in dim light

cone cells - responsible for colour perception

40
Q

Describe the process of absorbing a photo on light in the eye

A
  • retinal absorbed a photon of light to become photoexcited rhodopsin
  • this leads to the activation of the G proteins transducin
  • transducing activates the enzyme PDE
  • PDE catalyses the hydrolysis of cGMP, reducing its concentration
  • reduction in concentration form cGMP to GMP leads to the closure of the ion channel
  • the closure of channel leads to nerve impulse being fired
41
Q

how do rod cell respond to low intensities of light

A

they have high degree of amplification due to protein cascade

42
Q

what is the difference between rod and cone cells

A

cone cells contain different forms of opsin with maximal sensitivity to specific wavelengths of light

43
Q

what stages are involved in the interphase

A

G1 phase - cell growth
S phase - DNA replication
G2 phase - cell growth

44
Q

what stages are involved in the mitotic phase

A
prophase 
metaphase 
anaphase 
telophase 
cytokinesis
45
Q

what happens in the prophase

A

the nuclear membrane breaks down and spindle microtubules extend form the MTOC by polymerisation and attach to the chromosomes via there centromere

46
Q

what happens in the metaphase

A

the chromosomes line up at the equator of the cell

47
Q

what happens in the anaphase

A

the spindle microtubules shorten by depolymerisation and pull the chromosomes to opposite poles of the cell

48
Q

what happens in the telophase

A

the chromosomes decondense and the nuclear membrane reforms around them

49
Q

what happens in cytokinesis

A

the cytoplasm divides to create two new daughter cells

50
Q

What is a proteolytic cleavage

A

another type of post translation modification required to produce an active protein

51
Q

Describe the process of the pump in the small intestine

A
  • the sodium potassium pump releases the sodium ions outside the cell
  • a sodium ions gradient is then generated across the membrane
  • this gradients drives the active transport of glucose
  • the glucose transporter GLUT 4 then transports glucose and sodium across the membrane at the same time
52
Q

how does sodium and glucose move

A

glucose - against concentration gradient

sodium - down concentration gradient

53
Q

Describe the G1 checkpoint

A
  • cyclin combines with the CDK
  • Binding of cyclin activates CDK with causes phosphorylation
  • RB protein is inhibited by binding of phosphate
  • the non -phosphorylated RB protein is active
  • this allows the transcription factor to actor to be activated and make the proteins so cell cycle can move to S phase
54
Q

what is apoptosis

A

triggered death signal which involves the activation of caspases causing destruction of protein molecules of a cell

55
Q

give an example of internal apoptosis

A

DNA damage can not be repaired which triggers the activation of P53 protein

56
Q

give an example of external apoptosis

A

lymphocytes bind to to a receptor protein and trigger a protein cascade in the cytoplasm

57
Q

what is the importance of apoptosis

A

it is essential during early development of multicellular organisms

58
Q

what is a point count

A

involves observes recording all individuals seen form a fixed point. this can then be compared to other point count locations or the same place but different time

59
Q

what methods can be used for tracking organisms

A

tagging, painting, clipping or implantation

60
Q

How can allusive species be tracked

A

SCAT sampling, cameras or traps

61
Q

what is convergent evolution

A

involves similar structures which have evolved form different ancestors

62
Q

what is latency

A

the time between stimulus and response behaviour

63
Q

what is duration

A

the length of time the behaviour occurs

64
Q

what is frequency

A

the amount of times the behaviour occurs

65
Q

what is an ethogram

A

an ethogram is a way of recording animal behaviour over a set period of time

66
Q

what is anthropomorphism

A

applying human characteristic to non-human species

67
Q

what is natural selection

A

the increase in alleles which are beneficial and decrease in alleles which are disadvantageous

68
Q

what is evolution

A

the the change overtime in the proportion of individuals in a population differing on one or more trait

69
Q

what is sexual selection

A

a non-random process involving selection of alleles that increase the chances of mating and producing offspring

70
Q

what is sexual dysmorphism

A

when the male exhibits different characteristic from females

71
Q

what are the two forms of sexual selection

A

male rivalry increases access to females through conflict and female choice where females assess fitness of males

72
Q

what is genetic drift

A

when a chance events cause unpredicted fluctuation in allele frequency from one generation to the next

73
Q

what is co-evolution

A

co-evolved intimate relationship between members of two different species

74
Q

what is mutualism

A

both organisms in the interaction are interdependent on each other (+/+)

75
Q

what is commensalism

A

only one organisms benefit (+/0)

76
Q

what is parasitism

A

parasite benefits by gaining energy and nutrients from the host who is harmed (+/-)

77
Q

what is a benefit of sexual reproduction

A

Genetic variation provides chance for adaptation, giving offspring a better chance of survival under selection pressures

78
Q

what is a cost of sexual reproduction

A

only half of each parents genome is passed onto offspring disrupting successful parental genomes

79
Q

what is benefit of asexual reproduction

A

whole organism is passes onto offspring which allows survival in very narrow stable niches and can reproduce in larger numbers

80
Q

what is a cost of asexual reproduction

A

not able to adapt to changes in environment due to lack of variation

81
Q

what is an example of reproduction in prokaryotes

A

horizontal gene transfer which can lead to rapid evolutionary change

82
Q

what is an example of asexual reproduction in plants

A

vegetative reproduction

83
Q

what is an example of asexual reproduction in eukaryotes

A

parenthogenesis takes place in lower plants and animals which lack fertilisation. this allows just a female to fertilise her eggs. takes place in cooler and low parasite densities.

84
Q

Homologous chromosomes are?

A
  • same size
  • same centromere position
  • same sequence of genes at the same loci
85
Q

Meosis is the formation of ……. for a …….

A

haploid gamete

Diploid gametocyte

86
Q

Describes the stages involved in meosis I

A
  • homologous chromosomes condense and pair up
  • chiasmata forms ate points of contact and DNA is exchanged
  • linked genes are those on the same chromosome and can result in new combination
  • the crossing over is random and produced genetically different recombinant chromosomes
  • spindle fibres attach to centromere and line up and the equator
  • each chromosome is positioned randomly irrespective of their maternal or paternal origin. this is known as independent assortment
  • chromosomes separated and pulled apart to each pole of the cell
  • cytokinesis follows
87
Q

Describe meosis II

A
  • each of the two cells produced in meosis I undergo further cell division
  • a total of 4 haploid gametes are produced
88
Q

what gene switches on to to produce a male

A

SRY gene

89
Q

what is X chromosome inactivation

A

when one of the X chromosome randomly inactivates to prevent a double dose of genes being expressed which can be harmful to cells

90
Q

why are females less likely to get recessive traits

A

They have two X chromones so one will mask the effects of the recessive trait whereas males have one X and have no second copy to mask the effects

91
Q

what is a hermaphrodite

A

a species which have both male and female reproductive organs

92
Q

what is a benefit of a hermaphrodite

A

there is no requirement for the mate to be of opposite sex.

93
Q

how can environmental factors affects sex ratio

A

in reptiles egg incubation can determine sex in some reptiles

94
Q

what is a negative control

A

provides results in the absence of treatment

95
Q

what is a positive control

A

the treatment in includes to check that the system can detect positive results when it occurs

96
Q

how can reliability be ensured

A

carrying out independent replicates