Midterm Flashcards
(113 cards)
1
Q
G1 phase
A
Growth and cellular metabolism
2
Q
S phase (synthesis)
A
DNA replication, chromosomes duplication
3
Q
G2 phase
A
Prepare for mitosis
4
Q
M phase
A
Mitosis
5
Q
Interphase
A
Time between successive mitosis’s (G1+G2+S)
6
Q
G0 phase
A
Terminal event. eg. neutrons with axons and dendrites
7
Q
Why does mitosis happen
A
Growth, cell replacement, healing, reproduction
8
Q
Prophase
A
Chromosomes condense, centrosomes produce microtubules and migrate to opposite poles
9
Q
Pro metaphase
A
Microtubules attach to chromosomes and nuclear envelope begins to break down
10
Q
Metaphase
A
Chromosomes align in centre of cell
11
Q
Anaphase
A
Sister chromatids migrate to opposite poles
12
Q
Telophase
A
Nuclear envelope begins to reform, chromosomes condense
13
Q
meiosis I
A
Randomly separates chromosomes
14
Q
meiosis II
A
Separates sister chromatids like mitosis
15
Q
M cyclin
A
CDK helps prepare the cell for mitosis
16
Q
S cyclin
A
CDK helps initiate DNA synthesis
17
Q
G1/ S cyclin complex
A
Prepares the cell for DNA replication
18
Q
DNA replication checkpint
A
Checks for any un-replicated DNA at the end of g2 phase (before cell enters mitosis)
19
Q
Cell cycle check points
A
Cell replication pauses to make sure it is okay for the cell to go on to the next stage. There are specialized CDK complexes to do so
20
Q
DNA damage checkpoint
A
Checks for damaged DNA before the cell enters S phase, makes sure genes that inhibit the cell cycle are turned off
21
Q
Spindle assembly checkpoint
A
Checks that all chromosomes are attached to spindle fibres, after DNA replication checkpoint
22
Q
Oncogene
A
Cancer causing gene
23
Q
Proto- oncogene
A
Normal genes important for promoting cell division, but have the potential to become cancerous if mutated
24
Q
Tumour suppressors
A
genes that encode proteins whose normal activity inhibits cell division
25
Cancer development
Normal cells: Inactivation of the first tumour suppressor gene
benign cancer: Activation of the oncogene
Malignant/ metastatic cancer : Inactivation of the second and third tumour suppressor gene
26
Principle of dominance
In a heterozygote, one allele may conceal the presence of another
27
Principle of segregation
In a heterozygote, two alleles R and r separate themselves in the form of gametes
28
Principle of independent assortment
Alleles on different parts of chromosomes assort independently from one another (in anaphase I)
29
Addition
OR
30
Multiplicative
AND
31
Monogenic trait
When one gene is responsible for one trait
32
Polygenic trait
There are multiple genes responsible for a person's height
33
Prophase I
Synapse (gene-for-gene pairing)
Bivalent (crossing over)
Chromosomes condense and nuclear envelope begins to break down
34
Prometaphase I
Spindles attach to kinetochores on chromosomes
35
Metaphase I
Mono orientation
36
Anaphase I
Homologous chromosomes separate but sister chromatids do not
37
Telophase and cytokinesis (meiosis I)
Cells go from diploid to haploid
38
Prophase II
Nuclear envelope breaks down and chromosomes condense
39
Pro metaphase II
Spindles attach to the kinetochores on chromosomes
40
Metaphase II
Chromosomes align in the centre of the cell
41
Anaphase II
Sister chromatids separate, replication in policy has already happened
42
Telophase and cytokinesis (meiosis II)
Cytoplasm does not divide equally
Males: Each n cell is a sperm cell
Females: 3 polar bodies and 1 oocyte (egg)
43
Pedigree of autosomal dominant traits
Equal in males and females
Does not skip generations
Affected offspring will have an affected parent (unless they posses a new mutation)
44
Pedigree characteristics of autosomal recessive traits
Equal in both sexes
Skips generations
Affected can be born to unaffected children
Appears more frequently among children of consanguineous marriages
45
Human sex chromosomes
There is a small region of homology where pairing occurs
Y chromosome is our smallest chromosomes
They are not similar enough for any crossing over to happen
46
Y linkes traits
Only boys, passed form father to sons and does not skip generations
47
Nondisjunction
Results in eggs with either two X chromosomes or no X chromosomes
Rare XO males receive their X chromosomes from their fathers
48
DNA
Polymer: deoxyribose sugar
Phosphate group: 5' carbon (adds negative charge)
Nitrogenous base: 1' carbon
OH group: 3' carbon
49
Nitrogenous bases
Purines (double ring): Adenine and guanine
Pyridines (single ring): Cytosine and thymine
Pairing: AT (20%) and GC (30%) each
Hydrophobic
Connected by phosphidiester bonds
50
First level of condensation
Wrapped around histone proteins
51
Second level of condensation
Supercoiling due to nucleosomal interactions
52
Telomere
Protect the ends of chromosomes
Prevent the ends of chromosomes from fusing together
Facilitate replication of the ends of linear DNA
53
Central dogma
Information flows from DNA to RNA to proteins
54
Transcription
When RNA polymerase reads the strands of DNA and makes a new one
55
Centromeres
Hold chromosomes together. Satellite sequence (non- coding DNA)
56
Nucleotide
Group of 3 (one codon)
57
Third level
Attachment to non- histone protein scaffold
58
quaternary structure
Two or more polypeptide chains may form a double helix
59
RNA
Ribose sugar (OH on 2' rather than H)
Uracil replaces thymine, this makes RNA more reactive than DNA
60
RNA synthesis
RNA is synthesized on mRNA molecules, from DNA
1) Initiation of RNA synthesis does not require a primer
2) New nucleotides are added to the 3' end of the RNA molecule
3) DNA unwinds at the front of the transcription bubble and rewinds
61
Prokaryotic transcription
Can occur simultaneously by ribosomes
62
RNA splicing
Removes introns
63
TATA box
Promoter sequence
64
Post transcriptional modification
Addition of the 5' cap: Helps ribosomes bind to 5' end of mRNA
3' cleavage and addition of poly(a)tail: Increases stability of mRNA, facilitates binding of ribosome to mRNA
RNA splicing
65
How is genetic code read
No spaces between codons and they do not overlap
Most amino acids are specified by more than one codon
Nearly universal
Reading frame defined by an AUG codon near the 5' end of the RNA
66
Mutations
Can arise spontaneously as a result of an error during DNA synthesis or as a result of spontaneous chemical changes that alter the nucleotides
67
Co- dominance
The phenotype is between two homozygotes
68
Incomplete dominance
There is phenotype that is a mix of two alleles
69
Lethal allele
Causes death at an early stage of development, so some genotypes may not appear in the progeny. Heterozygotes are viable. Affects the mendelian genotypic/ phenotypic ratios among live births
70
Penetrance
The chance of an individual having a particular genotype that expresses a particular phenotype
71
Incomplete penetrance
When the phenotype does not relate to the genotype
72
Lethal allele
Causes death at an early stage of development, not common since no homozygous individuals live long enough to reproduce
73
Expressivity
The degree to which an allele is expressed
74
Polymorphism
An allele found in at least 1% of the population, the rest are mutant alleles
75
Wobble base pairing
When thymine and guanine pair together
76
Depurination
When A purine site does not provide template for T, so pairs with another A
77
Deamination
Removing NH2
Cytosine= uracil
5-methyl cytosine= thymine
78
Somatic mutations
Not passed on
79
Germ line mutations
Passed non
80
Missense
thq one big fly had one red eye
81
Nonsense
the one big
82
Strand slippage
New strand slips out... addition
| Template strand slips out.... deletion
83
Unequal crossing over
One chromosome has an insertion, one has a deletion
84
Types of chemical mutation
1) Only replicating DNA
| 2) Both replicating and non replicating DNA
85
Mutations that interfere with non- coding regions
Interfere with promoter function to prevent or reduce transcription
86
Recessive gene mutations
Almost always involve loss of gene function
87
Complete loss of function
Nut allele
88
Partial loss of function
Hypermorphic allele
89
Discontinuous characteristics
Relatively few phenotypes
90
Continuous characteristics
qualitative EG. hair/ skin
91
Polygenic characteristics
Genes influenced by genes on many loci
92
Multifunctional characteristics
Polygenic characteristics influenced by environmental factors
93
Blood
O can donate to anybody
AB can accept from anybody
I^a and I^b are co dominant over I
94
Radiation
Chromosome breaks
95
Transposable elements
Inserted into staggered cuts in the DNA, different mutations can cause the same disorder
96
Base analogues
Molecules that have a very similar structure to a nitrogenous base
5- broumacil may be inlace of thymine, if it pairs with guanine this is bad. If it pairs with adenine it is fine
97
Cleft lip/ cleft plate
Ultrasound
98
Amniocentesis
Amniotic fluid, cells are cultured, DNA analysis and chromosomal analysis are done
99
Chronic villus
Catheter is inserted through vagina into contact with the chorion (outer layer of the placenta). Suction removes a piece to be used for genetic tests (no need to be cultured)
100
Fetal cell sorting
Fetal cells can be sorted from maternal cells
101
Pre- implantation genetic diagnosis
Abnormal, combined with in vitro fertilization treatments. Sampling of cells at 8 or 16 cell stage
102
Cystic fibrosis
Amniocentesis or Chronic villus sampling
103
Dwarfism
ultrasound, X rays, Amniocentesis or Chronic villus sampling
104
Hemophilia
Fetal blood sampling, amniocentesis or Chronic villus sampling
105
Lesch-nyhan syndrom
amniocentesis or Chronic villus sampling
106
Neural tube defects
amniocentesis, ultrasound or maternal blood tests
107
Osteogenesis imperfecta
Ultrasound or X rays
108
Phenylketonuria
amniocentesis or Chronic villus sampling
109
Sickle- cell anemia
amniocentesis or Chronic villus sampling
110
Tay- Sachs disease
amniocentesis or Chronic villus sampling
111
Dominant mutations
Can involve a loss or gain of gene function
112
Loss of function mutation
For those genes where one functional copy is not enough (also called haploinsufficiency)
113
Dominant negative mutation
A loss of function mutation that interferes with the wild type allele
