Advanced Higher Biology Prelim Revision Flashcards
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
what are the two types of modulator
positive - increased affinity for substrate
| negative - decreases affinity for substrate
26
what is facilitated diffusion
is passive transport of molecules through transmembrane proteins form a high to low concentration
27
what molecules pass through the plasma membrane by diffusion
oxygen and carbon dioxide
28
describe the sodium potassium pump
- 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
what molecule are transported by hydrophobic signalling
steroid hormones such as oestrogen and testosterone
30
describe hydrophobic signalling
- 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
what molecules are transported by hydrophilic signalling
hormones such as insulin and neurotransmitters
32
Describe hydrophilic signalling
- 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
what is G-protein relay
G-protein relays signal form activated receptor to target proteins
34
what is phosphorylation cascade
involves series of events with one kinase enzyme activating the next and so on
35
describe the process of nerve impulse transmission
- 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
what is the charge of neuron when sodium floods out of cell
becomes more positive
37
what is charge of neuron when potassium floods into cell
more negative
38
what is charge of resting potential
more negative
39
what are the two photoreceptors in the eye and what is their purpose
rod cells - function in dim light
| cone cells - responsible for colour perception
40
Describe the process of absorbing a photo on light in the eye
- 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
how do rod cell respond to low intensities of light
they have high degree of amplification due to protein cascade
42
what is the difference between rod and cone cells
cone cells contain different forms of opsin with maximal sensitivity to specific wavelengths of light
43
what stages are involved in the interphase
G1 phase - cell growth
S phase - DNA replication
G2 phase - cell growth
44
what stages are involved in the mitotic phase
```
prophase
metaphase
anaphase
telophase
cytokinesis
```
45
what happens in the prophase
the nuclear membrane breaks down and spindle microtubules extend form the MTOC by polymerisation and attach to the chromosomes via there centromere
46
what happens in the metaphase
the chromosomes line up at the equator of the cell
47
what happens in the anaphase
the spindle microtubules shorten by depolymerisation and pull the chromosomes to opposite poles of the cell
48
what happens in the telophase
the chromosomes decondense and the nuclear membrane reforms around them
49
what happens in cytokinesis
the cytoplasm divides to create two new daughter cells
50
What is a proteolytic cleavage
another type of post translation modification required to produce an active protein
51
Describe the process of the pump in the small intestine
- 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
how does sodium and glucose move
glucose - against concentration gradient
| sodium - down concentration gradient
53
Describe the G1 checkpoint
- 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
what is apoptosis
triggered death signal which involves the activation of caspases causing destruction of protein molecules of a cell
55
give an example of internal apoptosis
DNA damage can not be repaired which triggers the activation of P53 protein
56
give an example of external apoptosis
lymphocytes bind to to a receptor protein and trigger a protein cascade in the cytoplasm
57
what is the importance of apoptosis
it is essential during early development of multicellular organisms
58
what is a point count
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
what methods can be used for tracking organisms
tagging, painting, clipping or implantation
60
How can allusive species be tracked
SCAT sampling, cameras or traps
61
what is convergent evolution
involves similar structures which have evolved form different ancestors
62
what is latency
the time between stimulus and response behaviour
63
what is duration
the length of time the behaviour occurs
64
what is frequency
the amount of times the behaviour occurs
65
what is an ethogram
an ethogram is a way of recording animal behaviour over a set period of time
66
what is anthropomorphism
applying human characteristic to non-human species
67
what is natural selection
the increase in alleles which are beneficial and decrease in alleles which are disadvantageous
68
what is evolution
the the change overtime in the proportion of individuals in a population differing on one or more trait
69
what is sexual selection
a non-random process involving selection of alleles that increase the chances of mating and producing offspring
70
what is sexual dysmorphism
when the male exhibits different characteristic from females
71
what are the two forms of sexual selection
male rivalry increases access to females through conflict and female choice where females assess fitness of males
72
what is genetic drift
when a chance events cause unpredicted fluctuation in allele frequency from one generation to the next
73
what is co-evolution
co-evolved intimate relationship between members of two different species
74
what is mutualism
both organisms in the interaction are interdependent on each other (+/+)
75
what is commensalism
only one organisms benefit (+/0)
76
what is parasitism
parasite benefits by gaining energy and nutrients from the host who is harmed (+/-)
77
what is a benefit of sexual reproduction
Genetic variation provides chance for adaptation, giving offspring a better chance of survival under selection pressures
78
what is a cost of sexual reproduction
only half of each parents genome is passed onto offspring disrupting successful parental genomes
79
what is benefit of asexual reproduction
whole organism is passes onto offspring which allows survival in very narrow stable niches and can reproduce in larger numbers
80
what is a cost of asexual reproduction
not able to adapt to changes in environment due to lack of variation
81
what is an example of reproduction in prokaryotes
horizontal gene transfer which can lead to rapid evolutionary change
82
what is an example of asexual reproduction in plants
vegetative reproduction
83
what is an example of asexual reproduction in eukaryotes
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
Homologous chromosomes are?
- same size
- same centromere position
- same sequence of genes at the same loci
85
Meosis is the formation of ....... for a .......
haploid gamete
| Diploid gametocyte
86
Describes the stages involved in meosis I
- 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
Describe meosis II
- each of the two cells produced in meosis I undergo further cell division
- a total of 4 haploid gametes are produced
88
what gene switches on to to produce a male
SRY gene
89
what is X chromosome inactivation
when one of the X chromosome randomly inactivates to prevent a double dose of genes being expressed which can be harmful to cells
90
why are females less likely to get recessive traits
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
what is a hermaphrodite
a species which have both male and female reproductive organs
92
what is a benefit of a hermaphrodite
there is no requirement for the mate to be of opposite sex.
93
how can environmental factors affects sex ratio
in reptiles egg incubation can determine sex in some reptiles
94
what is a negative control
provides results in the absence of treatment
95
what is a positive control
the treatment in includes to check that the system can detect positive results when it occurs
96
how can reliability be ensured
carrying out independent replicates
