Genetics Flashcards
1
Q
The study of heredity
A
Genetics
2
Q
Passing on characteristics (traits) from parents to offspring so offspring resemble parents and each other
A
Heredity
3
Q
Microbial Traits include… (4)
A
- Shape/Structure (morphology)
- Biochemical Reactions
- Movement and Behavior
- Interactions with other organisms
4
Q
Actual, expressed properties or characteristics
A
Phenotype
5
Q
Organisms genetic makeup (total collection of genes)
A
Genotype
6
Q
Total genetic material in a cell, total DNA or RNA
A
Genome
7
Q
Any factor affecting the expression of the phenotype other than the genes
A
Environment
Genotype + environment –> Phenotype
8
Q
Genes in cells are always composed of…
A
Double stranded DNA
9
Q
Genes hold the coded information that determines (4)
A
- The sequence of mRNA which determines the primary structure of a polypeptide
- The sequence of rRNA
- The sequence of tRNA
- The sequence of regulatory RNA
10
Q
The flow of biological information… (6)
A
- Genes (genotype)
- mRNA and other RNA
- Polypeptide primary sequence
- Proteins (enzymes)
- Regulates cell chemistry
- Determines morphology and phenotype
11
Q
Polymer of deoxyribonucleotides
A
DNA
12
Q
Polymer of ribonucleotides
A
RNA
13
Q
DNA and RNA differ in the… (2)
A
- Nitrogenous bases they contain
2. Sugars they contain
14
Q
DNA nitrogenous bases… (4)
A
- Adenine
- Thymine
- Cytosine
- Guanine
15
Q
True or Flase: In all cells DNA is always a double stranded helix?
A
True
16
Q
The purines are?
A
Adenine and Guanine
17
Q
The pyrimadines are…
A
Cytosine, Uracil, and Thymine
18
Q
Adenine and thymine are paired by…
A
2 hydrogen bonds
19
Q
Cytosine and Guanine are paired by…
A
3 hydrogen bonds
20
Q
How many base pairs make up one turn on the helix?
A
10 base pairs
21
Q
The diameter of double stranded DNA is?
A
2 nm
22
Q
RNA bases…
A
- Adenine
- Uracil
- Cytosine
- Guanine
23
Q
Nucleic Acids contain this type of bond?
A
Phosphoodiester
24
Q
RNA structure (single stranded?)
A
Most RNA molecules are single stranded, some are double stranded or have double stranded regions
25
3 types of RNA
1. mRNA
2. rRNA
3. tRNA
26
Characteristics of Viral Genomes
1. Either DNA or RNA- never both
2. Single stranded or double stranded
3. Very little or no proteins
4. Linear or circular
5. 20-100 genes
6. 20,000-100,000 nucleic acids
7. Viral genomes are packed within a capsid
27
What is a capsid?
Viral genomes are packed into a protein coat
28
Characteristics of Prokaryote Genomes
1. Double stranded DNA
2. 98% DNA and 2% proteins
3. Linear, circular, or supercoiled
4. Single piece of DNA as their bacterial chromosome
5. 2000-5000 genes
6. 2 -5 million nucleotides
7. Contain plasmids
29
What are plasmids?
Small pieces of open circular double stranded DNA in the cytoplasm
30
Eukaryotic Genome Characteristics
1. Always composed of double stranded DNA
2. Linear or circular
3. DNA is spread over many eukaryotic chromosomes
4. Several chromosomes
5.
31
All members of the same species have the same number of chromosomes?
Species Number or Chromosomal Number
32
What is the purpose of chromosomes?
Organizing a lot of DNA in a little volume
33
What are the components of the eukaryotic chromosome?
1. 35% DNA
2. 64% proteins (histones and non histones)
3. 1%RNA
34
DNA packing that is characterized by...
- During non dividing times
- Most loosely packed
- Individual chromosomes exist but are not visible
Chromatin
35
Levels of Eukaryotic Genomes (5)
1. Double stranded naked DNA (2nm)
2. Nucleosomes (10 nm)-
3. Solenoids (30 nm)
4. Supercoils (300 nm)
5. Chromosome
36
Nucleosomes are held together by...
Histone proteins
37
Solenoids are held together by...
Histone and non histone proteins
38
Supercoils are held together by...
Non histone proteins
39
Characteristics of DNA replication (3)
1. Complex process involving numerous proteins to ensure accuracy
2. 2 strands separate and serve as a template for synthesis of a complimentary strand
3. Each daughter gets one old stand and one new strand
40
When each daughter cell obtains one old strand and one new strand
Semi conservative
41
Characteristics of DNA synthesis in Bacteria
1. Bidirectional replication from a single fork
2. DNA is unwound at the replication fork
3. Circular
42
The entire genome in bacteria is replicated as a unit (no leading or lagging strands)
Replicon
43
Characteristics of DNA synthesis in Archaea
1. Circular
| 2. More than one origin
44
Characteristics of DNA synthesis in Eukaryotes
1. Linear
| 2. Many replication forks
45
Replication always proceeds in the __ to __ direction?
5--> 3
46
Function of Deoxyribonucleotide tri phosphates (monomers)
1. dATP, dCTP, dGTP, dTTP
| 2. Make the new stands of DNA
47
Provides the short segment of single stranded RNA and provides a 3' -OH
RNA primer
48
Type of RNA polymerase that makes the RNA primer
DNA primase
49
The region of single stranded DNA attached to a double stranded DNA, opens up so replication can begin
Replication bubble
50
The junction between single stranded DNA and double stranded DNA
Replication Fork
51
Where does DNA replication begin?
Origin of Replication
52
How many origins of replication are there in Prokaryotes?
1
53
How many origins of replication are there in Eukaryotes?
Multiple
54
- The first enzyme to assemble at the origin
| - Unwinds the DNA by breaking the hydrogen bonds between the bases on opposite strands
DNA helicase
55
-Enzyme that binds to single stranded regions of DNA behind the helicase to prevent it from coming back together before replication
Single Stranded Binding Proteins
56
-Enzyme that relieves tension in the double stranded DNA in front of the helicases to prevent the DNA from breaking before replication is accomplished
DNA topoisomerases
57
-Synthesizes a short stretch of complimentary RNA called the primer on each strand
Primase
58
What does the primer provide?
-Supplies a stable 3' -OH to which the main DNA polymerase can start to add dNTPs (new strand)
59
This enzyme starts to add the dNTP's complimentary to the ss DNA template to the 3' -OH end of the primer
DNA polymerase
60
DNA synthesis occurs in the...
5' to 3' direction
61
DNA replication occurs in the opposite direction on the 2 strands and this is called... leading and lagging strands
Bidirectional Synthesis
62
Characteristics of the leading strand...
1. Continuous Synthesis
| 2. Moves smoothly behind the helicase
63
Characteristics of the lagging strand...
1. Discontinuous synthesis
| 2. Each Okazaki fragment needs one primer
64
Synthesized strands on the lagging strand are called?
Okazaki Fragments
65
Enzymes that remove the RNA primers
RNAases
66
Enzyme that seals any nicks in the Phosphodiester bonds
DNA ligase
67
Enzyme that checks out the replication to see if any errors were made and they correct them
Mismatch Repair Enzymes
68
DNA polymerases require 3 things synthesis of the complimentary strand...
1. A template- directs synthesis for the complimentary strand
2. A primer (DNA or RNA) strand
3. dNTP's (deoxyribonucleotides tri phosphates)
69
This is a complex of 10 proteins
DNA polymerase III holoenzyme
70
3 proteins form a...
Core enzyme
71
How many core enzymes form a polymerase?
2
72
The function of Polymerase?
1. Catalyze synthesis
| 2. Proofreading for Fidelity
73
This enzyme is a type of topoisomerase, it introduces negative supercoiling to help compact the bacterial chromosome
DNA gyrase
74
Proofreading is carried out by what enzyme?
1. DNA polymerase III
75
Removal of mismatched base from 3' growing strand is accomplished via this type of activity
Exonuclease Activity
76
Replication stops when...
The replisome reaches the termination site on the DNA
77
This forms when the 2 circular daughter chromosomes do not separate
Catenanes
78
This enzyme temporaly breaks the DNA molecules so the strands can seperate
Topoisomerases
79
This enzyme solves the end replication problem by synthesizing DNA using an RNA template and an internal RNA template
Telomerase
80
What is the end replication problem? (3)
1. Shortening of a chromosome after each round of replication
81
How is the end replication problem solved in Eukaryotes?
1. By the enzyme telomerase
82
How is the end replication problem solved in Bacteria?
1. By disguising the ends of the linear chromosome
83
Error rates in cells are approximately...
10-8 or 10-11 errors per base inserted
84
Accuracy is due to... (2)
1. Complimentary base pairing
| 2. Proofreading by DNA polymerase
