Bio 5: Cellular Control Flashcards
(114 cards)
1
Q
Gene
A
Length of DNA that codes for one or more polypeptides
2
Q
Polypeptide
A
Polymer consisting of a chain of amino acids residues joined by peptide bonds
3
Q
Protein
A
Large polypeptide usually 100 or more amino acids. Some proteins consist of one polypeptide chain and some consist of more than one polypeptide chain.
4
Q
Transcription
A
mRNA is used.
Hydrogen bonds break
Catalysed by RNA polymerase
5
Q
Translation
A
Assembly of polypeptides at ribosomes. The sequence is dictated by codons on mRNA.
6
Q
Mutation
A
Change in the amount of, or arrangement of the genetic material in a cell
7
Q
Chromosome mutations
A
Changes to the structure of chromosomes and/or to their number
8
Q
DNA mutation
A
Changes to the genes due to changes in nucleotide base sequences
9
Q
Point mutation/substitutions
A
One base pair replaces another
10
Q
Insertion/deletion (frameshift)
A
One or more nucleotide pairs are inserted or deleted from a length of DNA
11
Q
Huntington disease
A
Expanded triple nucleotide repeat
Normal gene for Huntington protein - repeating CAG
Symptoms include dementia, loss of motor control
12
Q
Sickle cell anaemia
A
Point mutation on triplet 6 of the beta chains for haemoglobin.
13
Q
Cystic Fibrosis
A
Deletion of tripled base pairs, deleting an amino acid in the normal polypeptide
14
Q
Allele
A
An alternative version of a gene. At the same locus on the chromosome and codes for the same polypeptide but the change can alter the proteins structure.
15
Q
Silent mutation
A
The base triplet has changed but it still codes for the same amino acid, the protein is unchanged
16
Q
Operon
A
A length of DNA made up of structural genes and control sites.
17
Q
Structural genes
A
Codes for beta-galactosidase and lactose permease
Each has base pairs that can be transcribed into a length of mRNA
18
Q
Control sites
A
Operator region: switches on and off structural genes
Promoter region: RNA polymerase binds to it to begin the transcription of the the structural genes
19
Q
Homeobox genes
A
Controls the development of the body plan of an organism, including polarity and positioning of the organs
20
Q
Apoptosis
A
Programmed cell death
Enzymes break down cytoskeleton Cytoplasm is dense Membrane can changes to blebs Chromatin condenses Nuclear envelope breaks Breaks into vesicles Taken up by phagocytosis
21
Q
Meiosis
A
Reduction division
Four daughter cells
Half the number of chromosomes
They are haploid
22
Q
Bivalent
A
Pair of joined homologous chromosomes
23
Q
Chiasmata
A
The points where non-sister chromatids within a bivalent join, where they cross over
24
Q
Locus
A
Position of a gene on a chromosome
25
Crossing over
Prophase I
Non sister chromatids wrap and join at Chiasmata
Chromosomes break here
They rejoin their non sister chromatid in the same bivalent
26
Reassortment of chromosomes
Consequence of random distribution of maternal and paternal chromosomes at the equator
Each gamete is a different mixture of maternal and paternal
27
Reassortment of chromatids
Alignment at metaphase II determines their segregation at anaphase II
(After crossing over they are no longer identical)
28
Fertilisation
One ovum and 300 million spermatozoa
All genetically different
29
Genotype
The allele present within cells of an individual for a particular trait or characteristic
30
Autos ones
Chromosomes not concerned with determining sex
31
Homozygous
Two identical alleles for a gene
32
Heterozygous
Two different alleles of the same gene
33
Phenotype
Observed characteristics in an organism
34
Dominant
An allele is dominant if it is always expressed in the phenotype
35
Recessive
It is recessive if it is only expressed in the phenotype in the presence of another identical allele, or in the absence of a dominant allele
36
Codominant
Two alleles of the same genes are described as Codominant if they are both expressed in the phenotype of a heterozygote
37
Linkage
Two or more genes that are located on the same chromosome
| They are normally inherited together because they don't separate in meiosis
38
Sex linkage
A characteristic is sex linked if the genes that codes for it is in the sex chromosomes
39
Haemophilia A
Clotting factors
- factor VIII coded by a gene on X chromosome
Recessive allele expresses an altered protein
Increase in clotting time
Females with the recessive allele - carriers
Males with the recessive allele - haemophilic
40
Duchenne muscular dystrophy
DMD gene for muscle protein dystrophin is on the X chromosome
Boys often get muscle weakness in early childhood
Wheelchair by 10
Death due to complications by 20s
41
Sickle cell anaemia
Beta haemoglobin differ by one amino acid
When this haemoglobin is deoxygenated it becomes deformed and inflexible
After many cycles they becomes unusable
42
Epistasis
The interaction of different gene loci so that one gene locus masks or suppresses the expression of another gene locus
43
Antagonistic recessive Epistasis
The presence of a homozygous recessive gene at one locus prevents the second from being expressed even if the second is dominant.
The alleles at the first locus are described as Epistasic and those at the second are described as hypostatic
9:3:4 ratio
44
Antagonistic dominant Epistasis
The dominant allele at one locus prevents the expression of the gene at the second locus. The presence of one dominant allele at the first locus will mask the expression at the second even if the at the second there is homozygous dominant alleles.
12:3:1 or 13:3
45
Complementary Epistasis
Two genes at different loci need to be present in order to cause a particular phenotype.
Example:
C-R- = purple
46
Chi squared
Statistical test to find out if the difference between observed data and expected data is small enough to be due to chance
47
Discontinuous variation
Clear categories
Qualitative differences
Different alleles at a single locus have large effects on locus
Different gene loci have different effects on the phenotype
48
Continuous variation
Quantitative differences
| Traits that have continuous variation are controlled by two or more traits
49
Population
A group of individuals of the same species that can interbred
50
The Hardy Weinberg principle
To calculate allele frequencies
```
Assumes:
Population is large
Mating random
No selective advantage for any genotype
No mutation, migration or genetic drift
```
51
Selection pressure
An environmental factor that confers greater chances of survival to reproductive age on some members of the population
52
Stabilising selection
A type of natural selection in which allele and genotype frequency within populations stays the same because the organisms are already well adapted to their environment
53
Genetic drift
The change in allele frequency in a population as some alleles pass to the next generation and some disappear. This causes some phenotypic traits to become rarer or more common
54
Biological species concept
A group of similar organisms that can interbred and produce fertile offspring
55
Phylogenetic species concept
A group of organisms that has similar shape, biochemistry, stages of development and behaviour. They also occupy the same ecological niche.
56
Monophyletic group
One that includes an ancestral organism and all its descendants
57
Paraphyletic group
Includes the most recent ancestor but not all its descendants.
Reptiles is Paraphyletic as it exclude birds which are descendants of reptiles
58
Natural selection
The organisms that are best adapted to their environment are more likely to survive. The favourable alleles are passed to their offspring.
59
Artificial selection
Where humans select the animals with the desirable characteristics. They allows these animals to breed so therefore the offspring have the characteristics wanted.
```
In cows:
Milk yield measured
Progeny of bulls tested to see which have high milk yield daughters
Artificial insemination
Hormones to make many eggs
Invitro fertilisation
Surrogates
```
60
Translation
Assembly of polypeptides at ribosomes. The sequence is dictated by codons on mRNA.
61
Mutation
Change in the amount of, or arrangement of the genetic material in a cell
62
Chromosome mutations
Changes to the structure of chromosomes and/or to their number
63
DNA mutation
Changes to the genes due to changes in nucleotide base sequences
64
Point mutation/substitutions
One base pair replaces another
65
Insertion/deletion (frameshift)
One or more nucleotide pairs are inserted or deleted from a length of DNA
66
Huntington disease
Expanded triple nucleotide repeat
Normal gene for Huntington protein - repeating CAG
Symptoms include dementia, loss of motor control
67
Sickle cell anaemia
Point mutation on triplet 6 of the beta chains for haemoglobin.
68
Cystic Fibrosis
Deletion of tripled base pairs, deleting an amino acid in the normal polypeptide
69
Allele
An alternative version of a gene. At the same locus on the chromosome and codes for the same polypeptide but the change can alter the proteins structure.
70
Silent mutation
The base triplet has changed but it still codes for the same amino acid, the protein is unchanged
71
Operon
A length of DNA made up of structural genes and control sites.
72
Structural genes
Codes for beta-galactosidase and lactose permease
| Each has base pairs that can be transcribed into a length of mRNA
73
Control sites
Operator region: switches on and off structural genes
Promoter region: RNA polymerase binds to it to begin the transcription of the the structural genes
74
Homeobox genes
Controls the development of the body plan of an organism, including polarity and positioning of the organs
75
Apoptosis
Programmed cell death
```
Enzymes break down cytoskeleton
Cytoplasm is dense
Membrane can changes to blebs
Chromatin condenses
Nuclear envelope breaks
Breaks into vesicles
Taken up by phagocytosis
```
76
Meiosis
Reduction division
Four daughter cells
Half the number of chromosomes
They are haploid
77
Bivalent
Pair of joined homologous chromosomes
78
Chiasmata
The points where non-sister chromatids within a bivalent join, where they cross over
79
Locus
Position of a gene on a chromosome
80
Crossing over
Prophase I
Non sister chromatids wrap and join at Chiasmata
Chromosomes break here
They rejoin their non sister chromatid in the same bivalent
81
Reassortment of chromosomes
Consequence of random distribution of maternal and paternal chromosomes at the equator
Each gamete is a different mixture of maternal and paternal
82
Reassortment of chromatids
Alignment at metaphase II determines their segregation at anaphase II
(After crossing over they are no longer identical)
83
Fertilisation
One ovum and 300 million spermatozoa
All genetically different
84
Genotype
The allele present within cells of an individual for a particular trait or characteristic
85
Autos ones
Chromosomes not concerned with determining sex
86
Homozygous
Two identical alleles for a gene
87
Heterozygous
Two different alleles of the same gene
88
Phenotype
Observed characteristics in an organism
89
Dominant
An allele is dominant if it is always expressed in the phenotype
90
Recessive
It is recessive if it is only expressed in the phenotype in the presence of another identical allele, or in the absence of a dominant allele
91
Codominant
Two alleles of the same genes are described as Codominant if they are both expressed in the phenotype of a heterozygote
92
Linkage
Two or more genes that are located on the same chromosome
| They are normally inherited together because they don't separate in meiosis
93
Sex linkage
A characteristic is sex linked if the genes that codes for it is in the sex chromosomes
94
Haemophilia A
Clotting factors
- factor VIII coded by a gene on X chromosome
Recessive allele expresses an altered protein
Increase in clotting time
Females with the recessive allele - carriers
Males with the recessive allele - haemophilic
95
Duchenne muscular dystrophy
DMD gene for muscle protein dystrophin is on the X chromosome
Boys often get muscle weakness in early childhood
Wheelchair by 10
Death due to complications by 20s
96
Sickle cell anaemia
Beta haemoglobin differ by one amino acid
When this haemoglobin is deoxygenated it becomes deformed and inflexible
After many cycles they becomes unusable
97
Epistasis
The interaction of different gene loci so that one gene locus masks or suppresses the expression of another gene locus
98
Antagonistic recessive Epistasis
The presence of a homozygous recessive gene at one locus prevents the second from being expressed even if the second is dominant.
The alleles at the first locus are described as Epistasic and those at the second are described as hypostatic
9:3:4 ratio
99
Antagonistic dominant Epistasis
The dominant allele at one locus prevents the expression of the gene at the second locus. The presence of one dominant allele at the first locus will mask the expression at the second even if the at the second there is homozygous dominant alleles.
12:3:1 or 13:3
100
Complementary Epistasis
Two genes at different loci need to be present in order to cause a particular phenotype.
Example:
C-R- = purple
101
Chi squared
Statistical test to find out if the difference between observed data and expected data is small enough to be due to chance
102
Discontinuous variation
Clear categories
Qualitative differences
Different alleles at a single locus have large effects on locus
Different gene loci have different effects on the phenotype
103
Continuous variation
Quantitative differences
| Traits that have continuous variation are controlled by two or more traits
104
Population
A group of individuals of the same species that can interbred
105
The Hardy Weinberg principle
To calculate allele frequencies
```
Assumes:
Population is large
Mating random
No selective advantage for any genotype
No mutation, migration or genetic drift
```
106
Selection pressure
An environmental factor that confers greater chances of survival to reproductive age on some members of the population
107
Stabilising selection
A type of natural selection in which allele and genotype frequency within populations stays the same because the organisms are already well adapted to their environment
108
Genetic drift
The change in allele frequency in a population as some alleles pass to the next generation and some disappear. This causes some phenotypic traits to become rarer or more common
109
Biological species concept
A group of similar organisms that can interbred and produce fertile offspring
110
Phylogenetic species concept
A group of organisms that has similar shape, biochemistry, stages of development and behaviour. They also occupy the same ecological niche.
111
Monophyletic group
One that includes an ancestral organism and all its descendants
112
Paraphyletic group
Includes the most recent ancestor but not all its descendants.
Reptiles is Paraphyletic as it exclude birds which are descendants of reptiles
113
Natural selection
The organisms that are best adapted to their environment are more likely to survive. The favourable alleles are passed to their offspring.
114
Artificial selection
Where humans select the animals with the desirable characteristics. They allows these animals to breed so therefore the offspring have the characteristics wanted.
```
In cows:
Milk yield measured
Progeny of bulls tested to see which have high milk yield daughters
Artificial insemination
Hormones to make many eggs
Invitro fertilisation
Surrogates
```
