Genetics Flashcards
1
Q
what does DNA stand for?
A
deoxyribonucleic acid
1
Q
what are the four base in DNA?
A
Adenine
Thymine
Guanine
Cytosine
2
Q
draw a diagram of a section of DNA?
A
3
Q
what is the definition of chromosome ?
A
a single chain of DNA that has been coiled up into a thread like structure
4
Q
Define the term gene?
A
a specific section within DNA which codes for a specific protein
5
Q
what are introns ?
A
non coding genes that regulate gene expression
6
Q
what are exons ?
A
coding genes for DNA
7
Q
what is semi conservative replication ?
A
the original double stranded will divide into two parent stands and then join with a new strand
8
Q
what is the process of unwinding ?
A
DNA helicase breaks the hydrogen bonds between the nucleotide
the point after which the strands are separated is known as the replication fork
9
Q
what does DNA polymerase do ?
A
collect nucleotides and matches them with the complimentary pairs on the parent strand running a 5-3 prime direction
10
Q
what is the leading strand ?
A
the strand that is replicating in the direction of unwinding
11
Q
what is the lagging strand?
A
strands replicating in the reverse direction
12
Q
what does Primase do?
A
creates short segments of primers which bind to make up the sections of DNA
13
Q
what are individual section of primers called ?
A
Okazaki fragments
14
Q
what does DNA ligase do ?
A
a glue that seals the nucleotides together to make a continuous strand
15
Q
what is the cell cycle ?
A
Gap 1
Synthesis
Gap 2
Mitosis
16
Q
what is the process of mitosis ?
A
IPMAT
17
Q
what is interphase ?
A
cell growth
production of organelles
DNA replication
produces proteins necessary for mitosis
18
Q
what is prophase ?
A
chromosomes condense and become visible
each chromosome is comprised of 2 chromatids
spindle fibres begin to form
nuclear membrane begins to form
19
Q
what is metaphase?
A
chromosomes line up along the equator
20
Q
what is anaphase?
A
spindle fibres attach to the centromeres
spindle fibre pull chromatids to opposite pole of the cell
21
Q
what is telophase ?
A
chromatids group together
2 new nuclear membranes for
chromosomes unravel
Cytokinesis occurs
22
Q
what is cytokinesis in animals ?
A
membranes move inwards pinching two daughter cells apart
23
Q
what is cytokinesis in plants ?
A
cell membrane and wall is created
24
what is the role of DNA?
to provide the blue prints for proteins
25
what is different about RNA to DNA?
made of ribose sugar instead of deoxyribose
single stranded instead of double
uracil instead of thymine
normally shorter the DNA
26
what does transcription make ?
mRNA
27
what is the process of transcription?
- a small section of DNA is unwound and the hydrogen bonds are broken by helicase to expose the nucleotides
- RNA polymerase goes along and picks up free nucleotides and binds it to the complimentary base to form the mRNA
- RNA polymerase and the mRNA detaches whilst the DNA zips back up
-mRNA exits the nucleus through a nuclear pore.
28
what prime does RNA polymerase run and why ?
3-5 prime
so add RNA nucleotides instead of DNA nucleotides
29
where does RNA polymerase start and stop?
Promoter sequence
Terminator sequence
30
what is the methylated cap?
- an alter nucleotide that binds to the 5' end
-acts as a signalling molecule that can be reached by ribosomes
31
What is the poly A-tail?
- a sequence of many adenosines joined to the 3' end
-help stabilise and protect the mRNA
32
what is splicing ?
the process of removing introns and joining exons together
33
what is alternating splicing?
controls which exons are spliced together
34
what is translation?
the process of creating proteins from a template in the ribosome
35
what is the process of translation?
-the methylated cap allow the ribosome to attache to mRNA
-the ribosome reads three nucleotides at time called a codon
-tRNA then get the anticodon that matched the codon
-the tRNA has amino acids that join together to form polypeptide chains
-the polypeptide the coils up to for proteins
36
what is meiosis?
the process where a single cell divide twice to form 4 daughter cells.
37
what is the process of meiosis?
Prophase 1
metaphase1
anaphase 1
telophase 1
cytokines 1
Prophase 2
metaphase 2
anaphase 2
telophase 2
cytokines 2
38
what is prophase 1 ?
-homologous chromosomes pair up
39
what is metaphase 1?
-homologous pairs line up on the equator
-spindle fibres attach
40
what is anaphase 2?
-homologous chromosomes pulled to seperate side of the cell
-chromosomes copy and go to one side
41
what is telophase 1?
2 haploid cells begin to formed
42
what is cytokinesis ?
- 2haploid cell formed
43
what is prophase 2?
- spindle fibres join perpendicular to the first set of chromosomes
44
what is metaphase 2?
-chromosomes line up along the equator
-perpendicular to the first set
45
what is anaphase 2?
-chromosomes split at the centromere
-sister chromatids to seperate sides
46
what is telophase 2?
4 haploid daughter cells
47
what is the definition of gene expression?
different environment can effect organisms phenotypes even if they have the same genotype
48
what can effect gene expression?
different food, exercise, temperature, acidity, alkalinity
49
what is epigenetics?
the study of chemical modifications to the gene function that are not due to DNA sequencing changes
50
what is a mutation?
any change to the DNA sequence
51
what is a spontaneous mutation ?
during DNA replication there is chance for the wrong base to be copied
52
what is the definition of mutagens?
a substance that induces a higher then normal rate of mutation
53
what are the three categories of a mutagen ?
physical
chemical
biological
54
what are some example of physical mutagens and what do they do to cause a mutagen ?
- radiation: causes damage to the DNA
- UV light: distort the double helix
-x-ray: breaking or severing the DNA strands
55
what are chemical mutagens ?
- substitution of bases with other chemical or attaching chemical makers
- causes replication error, prevents transcription, enables transcription of different proteins
56
what are biological mutagens?
mutations caused by invasive pathogens such as bacteria and viruses
57
what are the types of mutagens
neutral: no affect to the coded product
deleterious : stop or alter the production of the protein
58
what is a point mutation ?
a change in DNA where only one nucleotide is altered
59
what are the types of point mutations ?
- silent
- neutral
- missense
- nonsense
60
what is a substitution mutation?
when one nucleotide is replaced by another
61
what is a silent mutation?
no change has occurred to the codon
62
what is the neutral mutation ?
a change has occurred but it still codes for the same amino acid
63
what is a missense mutation?
a mutation that has occurred resulting in a different amino acid being formed
64
what is a nonsense mutation?
when the mutation causes a new stop codon to be formed
65
what is an insertion ?
the adding of an extra base
66
what is deletion ?
the removal of a base
67
what are some chromosomal mutations?
chromosomal deletion
chromosomal inversion
duplication
translocation
68
what is chromosomal deletion?
a section os DNA is removed
69
what is chromosomal inversion?
a break in a chromosome occurs and then is reattached the wrong way
70
what is chromosomal duplication?
a section of chromosome occurs twice
71
what is chromosomal translocation?
part of the chromosome breaks off and reattaches to the wrong chromosome
72
what are the four ways variation occurs?
mutations
crossing over
independent assortment of chromosomes
sexual reproduction
73
what is crossing over?
The exchange of genes from the maternal and paternal chromosomes creates new genetic combination
74
what is the law of independent assortment ?
Chromosomes seperate independently of each other during meiosis which creates various different chromosomal combinations
75
what is sexual reproduction ?
fertilisation of 2 gamete occurs randomly
76
what is sexual selection ?
selection arising through preference of an individual characteristics
77
what is co-dominance?
both alleles are observed in the organism eg roan cows
78
what is incomplete dominance?
when two genes are present but neither are dominant eg pink flowers
79
what are multiple alleles ?
when there are more then 2 alleles for any particular characteristics eg blood groups
80
what is sex-linked inheritance ?
characteristics that are carried on the sex chromosomes
81
what is monogenetic inheritance ?
when a characteristic is controlled by one pair of gene eg curly or straight hair
82
what is polygenetic inheritance?
controlled by more then one gene
83
what is transgenic organism?
organisms that have had the DNA of a different species inserted into their genome
84
what are genetically modified organisms?
organisms that have had their DNA modified
85
what are restriction enzymes?
they cut the DNA at the recognition site to remove a certain section of DNA
86
what are sticky ends ?
they have over hanging ends that ensure DNA is inserted the correct way
87
what are blunt ends?
DNA cut straight across
88
what is ligation?
DNA ligase joins the DNA strands together to form recombination DNA
89
what is recombinant DNA used for ?
the production of insulin, human growth hormone, vaccines
90
how are GMOS produced ?
-DNA is inserted in to a vector
- Vectors are inserted to the host cell
- host cells incorporate recombinant DNA with their own DNA
91
what are agrobacteriums ?
they are used to transfer foreign DNA into plants
92
what are transgenic organisms used for?
pesticides/herbicides
prevent breeding
control feral animals
process of oil
disease resistant crops
vaccines
93
what is DNA profiling ?
a technique used to compare two or more bases sequences using short tandem repeats
94
what are short tandem repeats?
section in DNA that are non coding that get repeated
95
what is the process of genetic finger printing
-extract DNA from a sample
-STRs cut into sections using restriction enzymes
- amplified using PCR
-separated fragments through gel electrophoresis
96
what is the process of gel electrophoresis ?
-DNA is cut up using restriction enzymes
-fluorescent dye is added into samples
-samples are added into gel wells on the negative electrode end
-electricity is through the gel allowing the negatively charged DNA to attach to the positive electrodes
-DNA is viewed under UV light which cause it to go fluorescent
97
what is the definition of DNA sequencing?
determining the order of the nitrogen bases that make up the DNA molecule
98
what is the process of DNA sequencing (Sanger method) ?
1. denature the DNA
-heat up the stand to 98c
2. annealing the primer
-adding primers and reducing the temperature to 50c to allow primer to join to the single strand of DNA
3. synthesise the strand
-temperature is increased to 60c allowing the polymerase to synthesise the complementary base until a terminator base is added
4. denaturing
-temperature is increased to 96c to seperate the synthesised DNA from the template
5. cycles
-repeat step 1-4 util there are enough strands
6. fragments separated by gel electrophoresis in a cepillary tube
-smaller fragment reach the end first
7. fluorescing
-at the end, bases pass through a lazer causing them to go fluorescent to determine the terminator base
99
what is a terminator base?
a free nucleotide with an altered sugar that prevent a longer chain from forming it has a fluorescent tag on it to identify
100
when is polymerase chain reaction (PCR) used?
when there is not enough DNA to be tested
101
what is the process of polymerase chain reaction (PCR) ?
1. denaturing
- heated to 95c
-DNA separates into 2 complimentary strands
2. annealing
-primers are added and cooled between 50-60c causing primer to bind to a single strand of DNA
3. synthesis
-DNA polymerase is added and free nucleotides and heated to 72c
-DNA polymerase binds free nucleotides together to form a new section of DNA
102
what does DNA profiling do in agriculture ?
- disease resistant
-faster growth rate
-more quality and quantity
-tolerance to adverse conditions
103
what are the desirable traits of GMOs?
-resistance
-faster growth rate
-greater product quality and yield
-tolerance to adverse environmental conditions
104
what are the benefits to GMOs?
-improved crop productivity
-improved nutritional value
-better flavour
-fresher for longer
-less herbicides and pesticides on feed
105
how does DNA profiling and sequencing used in conservation ?
monitoring endangered species
assessing gene pools for breading programs
tracking change in biodiversity
quarantine
GMOs in conservation
control of disease vectors
control of feral pest
106
what are adverse effects of biotechnology ?
-effects non target organisms
-more rapid evolution of pesticide resistant species
-the possibility of gene flow from crop species to weed species resulting in super weeds
