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Biology 2 > Ch. 8.1 and 8.2: DNA Replication 8.3 Mutations > Flashcards

Ch. 8.1 and 8.2: DNA Replication 8.3 Mutations Flashcards

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1
Q

What are nucleic acids made up of?

A

Nucleotides

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2
Q

What are nucleotides made up of?

A

Made up of three parts and those are:
1. Five-carbon sugar(ribose or deoxyribose)
2. Phosphate group
3. Organic, nitrogen containing-base

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3
Q

What are five nucleotides?

A

adenine, A; guanine, G; cytosine, C; thymine, T; and uracil, U

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4
Q

Which one of five nucleotides only found in RNA?

A

Uracil, U

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5
Q

What do DNA and RNA stand for?

A

Deoxyribonucleic acid (DNA) and ribonucleic acid (RNA)

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6
Q

What are three differences between DNA and RNA?

A
  1. DNA has thymine (T); RNA has uracil (U)
  2. DNA is double-stranded; RNA is single-stranded
  3. DNA has deoxyribose; RNA has ribose
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7
Q

Name two possible base pairs for DNA

A
  1. Adenosine (A) pairs with thymine (T)
  2. Cytosine (C) pairs with guanine (G)
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8
Q

What is hydrogen bond?

A

bond holding a base pair together

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9
Q

What does sugar-phosphate backbone consist of?

A

phosphodiester bonds

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10
Q

How does hydrogen bond help DNA to function?

A

Hydrogen bonds of base pairs can be broken to unzip DNA so that information can be copied

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11
Q

How many copies does DNA contain?

A

Two copies

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12
Q

What does having two copies mean?

A

Information can be accurately copied and passed to next generation

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13
Q

What are purines?

A

Large bases of nucleotide that has double ring structure: adenine and guanine

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14
Q

What are pyrimidlines?

A

Small bases of nucleotide that has single ring structure: cytosine and thymine

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15
Q

What amount of each purines and pyrimidlines do DNA molecules have?

A

Equal amounts

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16
Q

What does Chargaff rule suggest?

A

Amount of A always equals amount of T, amount of C always equals amount of G

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17
Q

How are carbon on ribose and deoxyribose numbered?

A

They are numbered 1 to 5

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18
Q

What is ATP in DNA structure?

A

ATP is nucleoside triphophate that is produced in all cells and primary source of energy for all cells to function

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19
Q

What else can be used for energy?

A

GTP

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20
Q

What does diet do in DNA structure?

A

Diet is source of nucleoside in our cells that can be made into nucleotide for DNA replication or used for transcription for RNA molecules

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21
Q

What do enzymes do in digestive tract?

A

Enzymes in digestive tract break down nucletic acids into individual nucleosides

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22
Q

What is telomere?

A

region of repetitive DNA at end of every chromosome

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23
Q

What do telomers do?

A

Telomeres protect ends of chromosome from deterioration

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24
Q

When do telomeres shorten and why does it happen?

A

telomere regions shorten during DNA replication because there is gap left after removal of first 5 end primer

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25
Why do people age?
Because telomeres get shorter after every cell division
26
When do telomeres shorten faster?
When degenerative like cancer and Alzheimer occurs
27
What can cause increased cell division?
Chroninc inflammation such as stress
28
Do prokaryotes have telomeres?
No, because they have circular DNA
29
What is telomerase?
Enzyme found in stem cells and germ cells which replace telomere sequences
30
What cells produce telomerase?
Cancer cells produce them and that is why they are immortal
31
What is average length of single chromosome?
2 inches
32
What is total length of DNA per cell?
About 2.3 meters
33
What is the relationship between two strands of DNA that form double helix DNA molecule?
They are complementary to each other and each chain is mirror to each other
34
How strong is hydrogen bond?
They hold bases together and are weak bonds, therefore, it is easy to be seprated
35
What is complemantary strand of this DNA sequence 5′ GGTACCAGT 3'?
3'CCATGGTCA5'
36
What are 1-5 steps of DNA replication?
1. Replication begins at point of origin; in eukaryotes there are many points of origin 2. Enzyme called helicase unwinds the DNA 3. Section where DNA is unwound is called replication fork 4. Single-strand binding proteins stabilize separated strands of DNA 5. DNA polymerase moves along each strand of unwound DNA and adds correct complementary nucleotides
37
What are 6-8 steps of DNA replication?
6. DNA polymerase can only add new nucleotides to existing strand of DNA. 7. Therefore, primase adds small fragment of RNA (RNA primer) to initially separated DNA 8. RNA primer is complementary to DNA, and this is later replaced with DNA
38
What are 9-11 steps of DNA replication?
9. Since two DNA strands are antiparallel, one strand is oriented as 5 to 3 and other strand is oriented as 3 to 5 10. Polymerase can only add new nucleotides to 3 end of the new′ DNA strand; this is called leading strand 11. Opposite strand is called lagging strand
39
What are 12-15 steps of DNA replication?
12. Lagging strand must be replicated in discontinuous segments called Okazaki fragments 13. Each segment of lagging strand must begin with RNA primer, then polymerase can add nucleotides in the 5 to 3 direction (This is direction of new strand being formed) 14. Then each RNA primer is removed and replaced with DNA 15. Enzyme that covalently links new segments of DNA after RNA primer is removed is DNA ligase—forms phosphodiester bonds
40
What is topoisomerase?
Enzyme that is used to relieve supercoils in eukaryotic DNA as well as in prokaryotes that have circular DNA
41
How is topoisomerase used in viruses?
used to integrate viral DNA into genome of cell it is infecting
42
How many genes do people have for DNA enzyme repairs?
130 genes
43
What is proofreading?
Repairs enzymes comparing new DNA strand with original DNA strand and fixing any incorrect nucleotide
44
Does proofreading prevent DNA mutations completely?
No
45
What happens if DNA mutations occur?
1. Apoptosis (programmed cell death) 2. Immune cells that kill cancers 3. Disease
46
What are ways that alter genetic message encoded in DNA?
Point mutations and recombination mutations
47
What is point mutation?
These result from errors in replication, they can involve substitutions, additions, or deletions of nucleotides
48
What is recombination mutation?
These cause change in position of all or part of gene
49
In what chances will base pairs become mismatch during replication
one in every 100000 to 1 million chances
50
What does mismatch cause?
mismatch causes polymerase to pause, and then incorrect base pair enters exonuclease section of polymerase enzyme; it is proofreading
51
What else corrects DNA mutation?
Repair enzymes
52
What is mutagen?
substance that mutates DNA
53
What is carcinogen
substance that mutates DNA and also causes cancer
54
What can mutations alter and affect?
Mutations can alter genetic message and affect protein synthesis
55
How do mutations occur?
Mutations occur randomly in cell's DNA therefore they are mostly detrimental
56
In what cell types can DNA mutations occur?
Germ cells and somatic cells
57
What would happen if DNA mutations occur in germ cells?
These mutations will be passed to future generations and they are important for evolutionary change
58
What would happen if DNA mutations occur in somatic cells?
These are not passed to future generations but are passed to all other somatic cells derived from them
59
What are different types of DNA mutations?
1. Substitution changes identity of base or bases 2. Insertion adds base or bases 3. Deletion removes base of bases
60
What would be consequence of deletion or addition
frame-shift mutation results and these are extremely detrimental because final protein intended by message may be altered dramatically or it may not be made at all
61
What are transposable elements (TEs)?
they are sequences of DNA that can move or transpose themselves within cell
62
What is mechanism of transposition?
mechanism of transposition can be either “copy and paste” or “cut and paste"
63
What kind of organisms contain TEs?
All living organisms contain transposable elements (also called transposons or jumping genes)
64
In what area do TEs play role of?
TEs play significant role in phenotypic variation and evolution, but they can be detrimental to an organism
65
What would happen if mutagen causes sugar-phosphate backbone to break?
cell will try to repair this by adding DNA fragment to another piece of DNA
66
What would happen if cells add DNA fragment to another piece of DNA?
This can cause segments of DNA to be moved to entirely different chromosomes
67
What are exons?
sequences in gene that code for mRNA that will code for protein
68
Are introns part of RNA sequence?
Introns are removed and do not become part of RNA sequence
69
What are silent mutations?
Mutations in introns usually have no affect on protein
70
What cells kill cancer cells?
Natural killer cells can kill cancer cells
71
What is cystic fibrosis?
one mismatch base in gene that codes for chloride channels
72
What is Huntington’s disease?
insertion of multiple CAG repeats in gene on chromosome 4
73
What is Sickle cell anemia?
one mismatch in hemoglobin gene
74
What is cancer?
usually two or more mutations in genes that code for repair enzymes or in genes that affect cell cycle
75
What is Phenylketonuria (PKU)?
point mutation in liver enzyme gene, which causes brain damage. Babies are tested at birth for presence of enzyme that breaks down phenylalanine into tyrosine (amino acids)
76
What is Nonpolyposis colorectal cancer?
autosomal, dominant, repeated CA mutation in DNA repair enzyme gene, non-functional repair protein
77
How do we acquire DNA mutations?
1. Mistakes during DNA replication 2. Transposition 3. Inherited mutations (approximately 10% of all diseases) 4. Mutagens and carcinogens (most common causes of mutation) 5. Viruses

Biology 2 (5 decks)

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