Brainscape's Knowledge GenomeTM

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


See full index

BIOL 115 Final > From gene to protein > Flashcards

From gene to protein Flashcards

1
Q

What is the problem with the molecular language

A

There are 4 nucleotides vs 20 amino acids

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

How do you go from 4 nucleic acids into specifying the protein?

A

Different codons

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

Nucleic acids

A
  • Composed of nucleotides
  • Codons are based on 3 nucleotides that can be put into different combos to produce the 20 diff amino acids
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Genes

A

Info in DNA that specifies what the sequence of amino acids will be

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

Proteins are specified by

A

Our genes that are composed of codons

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

Protein Functions

A
  • Takes things out of the environment:
    -> Sugars, fats, other things one can consume/synthesize from different metabolites
  • Builds membranes, glycogen, other structure (working molecules)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

DNA main function

A

stores all the info for every protein in the cell

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

How can an “alphabet” of A, T, C and G give rise to millions of proteins?

A

The Codon - the unit of information

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

Singlet DNA code

A

4 possible amino acids

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Doublet DNA code

A

4^2 = 16 possible amino acids

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Triplet DNA code

A

4^3 = 64 possible amino acids (CODON)

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

How are codons translated into amino acids?

A

A genetic code for protein synthesis

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

Genetic Code

A

Set of rules by which info encoded in genetic material (DNA or RNA) is translated into proteins or amino acid sequences

  • Consists of Codons: sequences of three nucleotides (Triplet DNA code) that specify a particular amino acid or signal the end of protein synthesis.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

The genetic code is degenerate

A
  • Amino acids can be specified by more than one codon
    -> bc there are more amino acids than codons
  • TRP (UGG) = special bc it’s unique
    -> It has giant side chains
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

The genetic code is universal

A
  • Same GFP (Green Fluorescent Protein) gene in all cells
  • If you take fluorescent gene from jellyfish and put it into bacteria, yeast, or mouse
  • Putting a specific wavelength of light will excite the protein, it goes to a high energy state which makes a chemical reaction that produces light
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Because DNA is degenerate:

A
  • The DNA sequence can determine the polypeptide (protein) sequence
  • But polypeptide sequence cannot determine DNA sequence
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Why are codons mRNA

A

They have uracil instead of thymine

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

3 Stop Codons

A
  • Make sure that there are no random ends of proteins by telling the system that is building the protein where to stop
  • Stop codons don’t specify amino acids
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

How are the 64 codons organized

A

16 blocks

20
Q

What does each block specify

A

Each block specifies the 1st and the 2nd letter of the codon

  • There is variation in the 3rd
21
Q

Why don’t some mutations in a gene change the protein sequence

A

Bc mutation in the third letter of the codon may still code for the same amino acid.

22
Q

Sense (coding) strand vs. Template (antisense) strand

A

Sense: 5’ - 3’
Template: 3’ - 5’

23
Q
A
24
Q

What is the first codon in the sense strand

A

ATG/AUG in mRNA = Met Amino Acid

25
Q

Why do we look at the sense strand

A

It is where mutations are - so when we look at DNA, we look at sense strand to find out if there are mutations that change the protein

26
Q

How do you build sense strand from template strand

A
  • Substitute T for A
  • Substitute C for G
27
Q

How do you make an mRNA sequence

A
  • The mRNA sequence is a perfect copy of the DNA sense sequence except T is substituted with U (uracil)
  • SO: Substitute the T’s in DNA sense strand with U
28
Q

What happens to mRNA sequence of codons

A

They are translated into an amino acid sequence

29
Q

Why is Amino Acid Met special

A
  • all genes have the first codon as being AUG or ATG
  • first amino acid in every protein is always Met
30
Q

Gene Structure

A
  • Promotor: initiates transcription of a particular gene
  • Start codon = ATG/AUG (1 or more)
  • Transcribed gene (will be transcribed into RNA)
    -> sequence of nucleotides when broken up into 3 nucleotides represent the codons that get translated to protein sequence
  • Stop codon = 1 of 3
  • Terminator = rich in Adenines
    -> Adenine tail makes sure that when mRNA is translated, the RNA also has Adenine tail, won’t be digested from the back to the front
31
Q

Promotors

A
  • Make sure RNA polymerase finds the right place: It has specific sequences that act like the substrates of an enzyme
  • Promoter binds to RNA polymerase (Enzyme that makes a copy of the sense strand with U instead of T)
  • Promoter and start codon control where RNA polymerase will start transcribing the DNA sequence into an mRNA transcript
  • As soon as RNA polymerase starts to build mRNA, it releases from the promoter and works its way down the sequence, building the RNA
  • Promotor does not specify amino acids
32
Q

Transcription/sigma factor:

A
  • Recognizes the regions on the DNA where transcription should start (1st and 2nd sites) and makes sure a gene turns on
    -> Where it starts will change the primary sequence of the protein and its function
  • Transcriptions factors also recruit RNA polymerase (specifies where RNA polymerase sits down
  • There are 2 regions so it’s more specific and stays in the right place
  • These steps control gene expression and can produce alternative yet functional proteins that are highly specialized for a cell type/stage in development
33
Q

Transcription vs Translation

A

Transcription: DNA to RNA
Translation: RNA to Protein

34
Q

Protein synthesis (Translation)

A
  • Dynamic process
  • Translation machine = Ribosome
35
Q

Ribosome

A
  • Has large and small subunits
  • Giant series of enzymes that has 3 active sites
  • Link the sequences associated with nucleic acids and proteins mechanistically
36
Q

tRNA (transfer RNA)

A
  • Transfers amino acids to a mRNA molecule bound to a ribosome
  • Recognizes the mRNA /start codon AUG that corresponds to Anticodon (UAC)
  • It binds to mRNA long enough to allow a peptide bond to form, then it has to release
37
Q

A (Aminoacyl) site

A
  • Where the mRNA codon is recognized
  • tRNA and amino acid enter Active site
  • Amino acid charges tRNA
    -> Aminoacyl-tRNA syntheses catalyzes covalent bonding btw amino and tRNA
38
Q

P (Peptidyl) Site

A
  • Where peptide bonds are formed
  • Requires energy (ATP) to overcome the energy barrier so it can make a covalent bond between adjacent amino acids to form a peptide chain
    -> Does this by bringing in tRNA that is bound to an amino acid
39
Q

E (Exit) Site

A
  • Where you go indexing across
  • Complete polypeptide
  • tRNA that was used to recognize the codon is released
  • New tRNA enters
40
Q

Releasing the Polypeptide

A
  • Ribosome reaches a stop codon (UAG, UAA, UGA) on the mRNA
  • Release factor (bound to GTP) facilitates Hydrolysis of GTP
    -> Hydrolysis reaction provides energy needed for the release factor to catalyze the release of the polypeptide chain from tRNA
  • Free polypeptide
  • Ribosome subunits and other components dissociate
41
Q

Why can Ribosome dissociate

A

Because it is an enzyme

42
Q

A polypeptide must be folded correctly for the protein to function

A
  • Polypeptides fold with help from helper proteins so they make less mistakes
    -> If it makes too many mistakes early on: proteins tends to be degraded bc there are sites that are exposed on it that can be digested by enzymes
  • Need to fold to get their hydrophobic areas away from water and their hydrophilic areas closer to water
    -> NOTE: this is how secondary structure occurs
43
Q

Where does the folding of a polypeptide happen

A
  • Cytoplasm (aqueous part of the cell)
    OR
  • Inside of a Membrane Compartment
44
Q

How a single mutation in DNA can change the shape and function of a protein - Point Mutations

A

1) Silent: change in third codon

  • Has no effect on protein sequence

2) Missense: results in amino acid substitution

  • Acidic to Basic/Uncharged to Charged so Protein function might change

3) Nonsense: substitutes a stop codon for an amino acid

  • Protein truncated, loss of function
45
Q

Frameshift mutations

A
  • Different protein, or a truncated protein
  • Loss or Gain of function
  • Cause of many diseases
  • Because DNA sequence read from 5’ to 3’, everything past that mutation will be wrong (lost or a different sequence)

BIOL 115 Final (5 decks)

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