Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

BIO112 > Unit 3 Chapter 15: How Genes Work/The Genetic Code/Mutations > Flashcards

Unit 3 Chapter 15: How Genes Work/The Genetic Code/Mutations Flashcards

1
Q

What is Alkaptonuria

A
  • discovered by Archibald Garrod
  • a rare inherited genetic disorder in which the body cannot process the amino acids phenylalanine and tyrosine, which occur in protein
  • Garrod figured it was out it was caused due to a lack of an enzyme
  • lead to the one gene, one enzyme hypothesis
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What was the one gene one enzyme hypothesis

A
  • Beadle and Tatum
  • each gene contains info to make an enzyme
  • discovered this by knocking out genes by damaging them and observing the phenotypes of the mutant cells
  • used radiation, found that mutants could not make certain compounds which they found was due to defects in a single gene which caused lack of an enzyme
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

How was the one gene one enzyme hyp. tested

A
  • used the synthesis of arginine as it requires various enzymes
  • raised colonies of irradiated cells in an arginine environment , then transferred a few to an environment that lacked it (to determine whether the cells could make their own or not)
  • then grew the cells in a non-arginine environment and supplemented them with either nothing, ornithine, citrulline or arginine.
  • some were able to grow on some of media but not on others (due to lack of specific enzymes)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What is the updated term for the one gene one enzyme hyp.

A

one gene one protein(or polypeptide)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What is mRNA

A
  • messenger RNA

- carry info from DNA to site of protein synthesis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What is RNA polymerase

A

enzyme that polymerizes ribonucleotides into RNA according to info given by sequence of bases in DNA
-does not need a primer

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What is the central dogma

A
  • summarizes flow of info in cells
  • DNA codes for RNA which codes from proteins
  • links genotypes to phenotypes
  • says that genotypes are determined by bases in DNA and phenotypes are a product of proteins produced
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What is transcription

A

the process of copying info in DNA to RNA

-DNA is transcribed to RNA by RNA polymerase

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What is translation

A
  • process of using the info in nucleic acids to synthesize proteins
  • mRNA is translated to proteins in ribosomes
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What are the 2 modifications to the central dogma

A
  1. many genes code for RNA molecules that do not function as mRNAs-they are not translated into proteins
  2. sometimes info flows from RNA back to DNA
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What is reverse transcriptase

A

a viral enzyme/polymerase that synthesizes a DNA version of RNA genes when an RNA virus infects a cell
-info flows from RNA to DNA

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What is the genetic code

A

the rules that specify the relationship between a sequence of nucleotides in DNA or RNA and the sequence of amino acids in a protein

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

How many bases make up one “word” in the code

A

3, because 4x4x4=64 which is more than enough info to code for all 20 amino acids; multiplying by 4 because 4 types of bases

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What is a codon

A

group of 3 bases that specifies a particular amino acid

-many codons can code for the same amino acid (the code is redundant)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What is the start codon

A

AUG signals start of protein synthesis

-methionine

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What are the stop codons

A
  • UAA, UAG, UGA

- signal that protein synthesis is complete

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What are the 4 main attributes of the genetic code

A
  1. it is redundant (all acids except methionine and tryptophotan) are coded for by more than one codon)
  2. it is unambiguous (a single codon never codes for more than one acid)
  3. it is nearly universal (works in almost all organisms)
  4. it is conservative (if more than 1 codon specifies the same acid, the first 2 bases are almost always the same)
18
Q

How do you use the genetic code

A

given a DNA sequence, translate the bottom strand (write the base pair) to create RNA (remember U will bond to A), then use the code to translate the RNA into proteins

19
Q

What does “the genetic code is degenerate” mean

A

the DNA sequence uniquely determines the amino acid sequence but the amino acid sequence does NOT uniquely determine the sequence of DNA

20
Q

What is tRNA

A
  • transfer RNA
  • contains an anticodon sequence (little loop of 3 nucleotides) that is the reverse complement of the codon for that amino acid sequence
  • at least one for each amino acid
  • allows ribosome to interpret RNA sequence
21
Q

What is a mutation

A

any permanent change in an organism’s DNA, changes genotype and creates alleles

22
Q

What is a point mutation

A

a single base change in the code

-can affect something like coat colour in mice

23
Q

What are missense mutations

A

point mutations that cause changes in amino acid sequences of proteins

24
Q

What is a silent mutation

A

a point mutation that does not change the sequence of an amino acid (ie. if it happens at the 3rd base of the codon)

25
Q

What is a beneficial mutation

A

mutations that increase an organisms fitness (ability to survive and reproduce)

26
Q

What is a neutral mutation

A

mutations that have no affect

ie.silent mutation

27
Q

What are deleterious mutations

A

mutations that lower fitness

28
Q

What is polyloidy

A

changing in the # of each type of chromosome

29
Q

What is aneuploidy

A

addition or deletion of a chromosome

30
Q

What is chromosome inversion

A

when segments of chromosomes become flipped and rejoin

31
Q

What is chromosome translocation

A

when segments of chromosomes become attached to different chromosomes

32
Q

What causes Sickle Cell Anemia

A

a change in the hemoglobin amino acid sequence

-single base pair change

33
Q

What is a nonsense mutation

A

when one of the amino acid codons is changed to a stop codon

34
Q

What is a deletion

A

a base is deleted, can cause a frame shift

a codon is deleted, no frame shift

35
Q

What is an insertion

A

a base or codon is inserted and causes a frame shift

36
Q

What are mutagens

A

agents that cause changes in DNA sequence

37
Q

What are somatic mutations

A

may kill a cell, disable it or make it cancerous. Transmitted to daughter cells but not to progeny.

38
Q

What are germ line mutations

A

can be transmitted to progeny and become a polymorphism in the gene pool

39
Q

How can DNA hold so much info

A

its info is in code form

40
Q

Why did researchers suspect that DNA doesn’t code for proteins directly

A

DNA is in nucleus but proteins are made outside of the nucleus

41
Q

What would happen if you mutate the anticodon of a tRNA, say from the codon for serine to the codon for phenyalanine

A

the synthase will still charge the mutant tRNA with serine but the serine will be incorporated into the protein where phenylalanine should be

BIO112 (19 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions