Chapter 8 - Genetics Flashcards
1
Q
What is genetics?
A
Science of heredity and gene function
2
Q
Who is the father of genetics?
A
Gregor Mendel
3
Q
Where are genes found?
A
Chromasomes
4
Q
How many DNA molecules are on 1 chromosome?
A
1
5
Q
How many pairs of chromosomes are in each human cell?
A
23
6
Q
What are DNA and RNA molecules made of?
A
Nucleiotides
7
Q
What 3 elements make up a nucleotide?
A
- nitrogenous base
- phosphate group
- sugar (deoxyribose or ribose)
8
Q
What are the nitrogenous bases of DNA?
A
Adenine
Cytosine
Guanine
Thymine
9
Q
What are the nitrogenous bases of RNA?
A
Adenine
Cytosine
Guanine
Uracil
10
Q
What shape is DNA?
A
Double helix
11
Q
What shape is RNA?
A
Single linear
12
Q
What bonds the nitrogenous bases to each other?
A
Hydrogen bonds
13
Q
What is the name of the genetic information of the cell and knowing what each gene codes for?
A
Genome
14
Q
What is Genomics?
A
The study of gene sequencing and molecular characteristics of genome
15
Q
What are chromosome pairs 1-22 called?
A
Autosomes
16
Q
What is the 23rd chromosome known as?
A
The sex chromosome
17
Q
What does XX code for?
A
Female
18
Q
What does XY code for?
A
Male
19
Q
What determines base sequences on DNA or RNA?
A
Genetic Code
20
Q
What is the general sequence of DNA coding?
A
DNA - transcription - RNA - translation - protein
21
Q
Where does transcription take place?
A
In nuclear area
22
Q
Where does translation take place?
A
In cytoplasm
23
Q
Does DNA or RNA carry the genetic code?
A
RNA
24
Q
What reads genetic code?
A
Ribosomes
25
What are codons?
Triplet bases of genetic code (ex. AUG)
26
For what does each codon code?
Specific amino acid
27
What is Degeneracy of Code?
The idea that some parts of the genetic code are redundant; more than one codon can code for the same protein
28
What is the genotype?
The actual genetic makeup
29
What is phenotype?
Physical characteristics coded for by genotype
30
If a gene is AA, what is it classified as?
Homozygous dominant
31
What is Aa classified as?
Heterzygous dominant
32
What is aa classified as?
Homozygous recessive
33
What is the official name for a double chromosome?
Diploid
34
What is the official name for a single chromosome?
Haploid
35
How does DNA Replication work?
- double helix splits
- Replication begins at replication fork
- DNA polymerases bring complementary nucleotides and proofread mistakes
36
How many replication forks do proks have?
One
37
How many replication forks do euks have?
Many
38
One DNA molecule makes how many double stranded DNA molecules?
2
39
What makes the flow of genetic information through generations possible?
Semi-conservative replication (of DNA)
40
Is 3' or 5' read first?
3'
41
In DNA replication, which strand is formed from the outside to the replication fork?
Leading Strand
42
In DNA replication, how does the lagging strand operate?
From the replication fork to the outside
43
Which bacteria replicates DNA bidirectionally?
E. coli
44
What does it mean to replicate bidirectionally?
Have 2 replication forks, each with leading and lagging strand
45
Does RNA replication work the same as DNA replication, why or why not?
No, 1 double strand of DNA vs. 2 single strands of RNA
46
What are the three types of RNA?
rRNA - ribosomal
tRNA - transport
mRNA - messenger
47
What is the primary function of rRNA?
Makes up ribosomes
48
What is the primary function of tRNA?
Bring amino acids back to the ribosome
49
What is the primary function of mRNA?
Translation
50
What does the expression of genetic information for a specific protein depend on?
Genetic code on mRNA
51
Why are proteins made only as needed?
It takes a lot of energy
52
What controls when and which proteins are made?
Cells themselves through repression systems that inhibit RNA polymerase
53
Do proks use the entire DNA molecule as a template to make RNA?
Yes
54
Do euks use the entire DNA molecule as a template to make RNA?
No
55
What are exons?
Regions of DNA molecule used to make RNA
56
What is the name of the regions of a DNA molecule that aren't used to make RNA?
Introns
57
What are mutations?
Changes in genetic info
58
Do mutations change the genotype?
Yes
59
Do mutations change the phenotype?
Sometimes
60
Are mutations generally positive, negative, or neutral?
Generally positive, some of all
61
Why do most positive mutations occur?
Adaptation, increase survival
62
What is the name of a base-pair substitution mutation?
Missense mutation
63
What happens in a missense mutation?
A different protein is coded for, energy is wasted
64
What is a frame shift mutation?
Insertion, deletion, or translocation of nucleiotides; makes different protein
65
What is the name of the mutation that puts a stop codon where it should not be?
Nonsense mutation
66
If a mutation is deadly, what is it called?
Lethal mutation
67
What is a mutagen?
Anything that directly or indirectly causes a mutation
68
What is a mutant?
Something that has already mutated
69
What is mutation rate?
Probability that a gene will mutate in DNA replication
70
How common are mutations?
Rare
71
What are 2 possible ways to identify mutants and how do they work?
1. Positive/Direct Selection - select for mutant by eliminating non-mutant (ex. penicillin in media, only resistant organisms will grow)
2. Negative/Indirect Selection - select for mutant based on mutant's inability to undergo a certain biochemical reaction (ex. mannitol fermentor mutated to be unable to ferment mannitol)
72
What are the benefits of testing for mutagens over carcinogens?
Carcinogen tests are long and costly, mutagen tests are not and most mutagens are carcinogens
73
What percent of mutagenic substances are also carcinogenic?
90%
74
What is the Ames Test?
A mutagenic test that tests for several properties
75
What are the 3 interchangeable terms that describe the exchange of genetic information between DNA molecules either within cells, between cells, or between organisms?
Genetic Recombination, DNA recombination, and Biotechnology
76
What is the Vertical Gene Transfer?
The idea that one generation passes genes to the next generation (e.g. parents to children)
77
When does Vertical Gene Transfer occur in humans?
Meiosis - Prophase 1
78
What is Horizontal Gene Transfer?
A lateral transfer of genetics from one organism to another of the same generation
79
In Horizontal Gene Transfer, what are the two roles an organism can assume?
Donor cell - giving genetic information
| Recipient cell - receiving genetic information
80
Once a recipient cell has received transferred DNA, what is it called?
A hybrid or recombinant cell
81
What is transformation?
When a donor cell lyses and a recipient cell takes in their genetic information
82
What 3 genera of bacteria can undergo transformation?
Streptococcus
Bacillus
Haemophilus
83
What is the major disadvantage of transformation?
The donor cell dies and not all info makes it into the recipient cell
84
How does conjugation work?
Donor cell extends pili and transfers genetic info
85
What 3 things does conjugation require?
Plasmid (extrachromosomal DNA), pili, cell to cell contact
86
Do G- or G+ cells have pili?
Only G-
87
What are the advantages of conjugation?
Donor doesn't die and more genetic info makes it to the recipient
88
How does transduction work?
Requires virus (phage) to inject info into recipient cell
89
What are the 5 steps of transduction?
1. Phage inserted into lytic cell
2. Recipient DNA destroyed by viral enzymes
3. Recipient cell's reproductive machinery used to replicate phage DNA
4. Recipient cell packages viral DNA into capsids
5. Recipient cell is lysed and virulent phages are released
90
How does the lysogenic cycle work?
The phage DNA enters recipient cell and chills; becomes incorporated into host DNA - prophage; replicates with host
91
What is the name of a daughter cell with combined DNA from its parents and the virus?
Temperate phage
92
Do temperate phages infect other host cells?
NO
93
What is a lysogenic cell?
Any cell that undergoes lysogeny
94
What happens to lysogenic cells?
They remain lysogenic until they are triggered into lytic cells
95
Is lysogeny good or bad for the lysogenic cell?
Good, it gives them advantages
96
What are some of the advantages of lysogenic cells?
- immune to infection by the same type of virus
- Gain new properties
- gain new genes that increase chances of survival
97
If a cell gains new properties because it is lysogenic, what is that called?
Phage conversion
98
What is an example of phage conversion?
C. diptheriae - only disease causing when it produces a toxin that is triggered by the presence of a certain virulent phage
99
What is a plasmid?
Extrachromosmal circular piece of DNA that carries genetic info to increase survival
100
What are the 3 types of plasmid?
1. f factor
2. Dissimilated
3. R factor
101
What does an f factor plasmid do
fertility - allows cells to make pili
102
What does a Dissimilated plasmid do?
allows organisms to use different carbon or energy source
103
What is an R factor plasmids function?
resistance - code for enzymes that inactivate toxins or medications
104
There is a fourth unnamed plasmid, what are its 2 functions?
1. make a pathogen more variolent
| 2. turn non-pathogen into pathogen
105
What is variolancy?
The degree of pathogenicity
106
Where are plasmids frequently used?
Biotechnology
107
What are transposons?
Small fragments of DNA that can be moved
108
What are the 3 ways transposons can move?
1. one area of the chromosome to another
2. one chromosome to another on the same organism
3. from a chromosome to a plasmid
109
What is "jumping genes" the nickname of?
Transposons
110
Several transposons may make up what?
A plasmid
111
Transposons can wreak havoc in what?
The gene sequence
112
Extrachromosomal agent of chaos in cells
Transposons
113
Up to a certain point, what controls genes?
Cells themselves
114
Within one cell or between cells, what 4 things can happen to genes?
1. Alteration
2. Deletion
3. Insertion
4. Translocation
115
Genes increase variety, which in turn does what?
Increases diversity
