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Biology > Chapter 12 > Flashcards

Chapter 12 Flashcards

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AP® Biology flashcards Biology 101 flashcards
1
Q

We can look at gene function in two ways

A

Molecular function of the protein

Organisms trait

They are connected, the molecular function affects the structure and function of cells

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2
Q

Polysome

A

One mRNA and many ribosomes

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3
Q

Unit of heredity

A

Another name for a gene

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4
Q

Two things genes do

proteins, template for

A

Store the info to make proteins

Act as a template to make an RNA molecule

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5
Q

Mutations

A

Changes in genetic material that can be inherited. It may change genetic blueprint by altering gene function

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6
Q

Archinold garrod and the relationship between genes and enzymes

Studied the disease
What the disease causes
What he hypothesized the disease was the result of

A

Alkaptonuria which causes abnormal levels of homogentisic acid(alkapton)

Causes discoloration of skin and urine to be black

Due to a missing enzyme, called it an inborn error of metabolism which is
A mutation in a gene that’s inherited by one or both parents

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7
Q

Beasley and Tatum
Proposed WHAT hypothesis
Describe their experiment, with bread mold neurospora

A

One gene, one enzyme; genes carry the info to make enzymes so a mutation in a gene would cause a defect in an enzyme

The bread mold needs a carbon source(sugar) inorganic salts and biotin.
They found every mutation resulted in the need for a vitamin to be supplemented

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8
Q

Beadle and Tatum

Amino acid arginine 
Sequence of conversions
Group 1
Group2
Group 3
A

Arginine needs 3 enzymes to grow,
Sequence of conversions
EnZyme 1 converts a precursor into”orinthine “, enzyme 2 converts to citrulline, and enzyme 3 converts to arginine.

Group 1 was missing the first enzyme. It would grow if o, c or a was added

Group 2 was missing enzyme 2. Wouldn’t grow if only orinthe was missing but would grow if c or a was added
Group 3 missing enzyme 3 could only grow if arginine was added

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9
Q

4 ways the one gene one enzyme hypothesis was modified

Modified slogan

A
  1. the info to make all proteins including enzymes is in genes
  2. some proteins are made of 2 or more polypeptides
  3. A single gene can encode more than 1 polypeptide. Sometimes due to the way rnas are spliced
  4. Some genes encode RNAs that form things other than protein, like ribosomes

One gene, one polypeptide

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10
Q

Polypeptide
Polypeptide denotes_____
Protein denotes —-
Protein activity determines

A

A linear sequence of amino acids. Polypeptide denotes structure, protein denotes function
The structure and function of cells

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11
Q

How proteins made of one polypeptide differ from those made with more

A

In those ones one gene contains all the info to make the whole protein

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12
Q

Hemoglobin

A

The protein that carries oxegyn in red blood cells. Made of 2 xglobin and 2 bglobin polypeptides

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13
Q 
Central dogma
( steps of gene expression at molecular level)
A
  1. Transcription- messenger RNA (mRNA) specifies the amino acid sequence of a polypeptide.
    Translation - uses mRNA template to make a polypeptide. Called translation because nucleotide sequence in mRNA is translated into an amino acid sequence of a polypeptide

DNA->RNA-> protein

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14
Q

Central dogma summary

A

The transcription of DNA into mRNA and the translation of mRNA into a polypeptide

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15
Q

mRNA is an example of a ____ gene
What do those genes do

Two important products of non structural genes

A

Structural gene
Code for polypeptides

Transfer RNA which translates the language of mRNA into amino acids
and ribosomal RNA which forms part of ribosomes where translation occurs

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16
Q

tRNA

rRNA

A

Transfer RNA translates mRNA into amino acids

Ribosomal RNA part of ribosomes

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17
Q

Stages of transcription

Prokaryotes

A

Initiation, recognition step
In bacteria sigma factor causes RNA polymerase to recognize promoter region
Stage completed when DNA strands separate near promoter to form open complex

18
Q

Transcription second stage(prokaryotes)
Which strand is used
What base pair is subsitutied

A 
Elongation
RNA polymerase synthesizes RNA
Template or coding strand used for RNA syntheses 
Synthesized to 5' 3'
Uracil is substatitute for thymine
19
Q

Transcription stage 3(prokaryotes)

A

Termination
RNA polymerase reaches the termination sequence
Causes both the polymerase and newly made RNA transcript to dissociate from the DNA

20
Q

The main purpose of the genetic material is

A

To encode the production of proteins in the correct cell, at the right time, in the right amount

21
Q

A gene at the molecular level is defined as

A

An organized unit of DNA to be transcribed into RNA and ultimately result in a functional product

22
Q

In eukaryotic cells ( transcription)
Polymerase 1 and 3
Polymerase 2

A

Polymerase 1 and 3 transcribe nonstructural genes

Poly 2 transcribes structural genes, transcribes mRNA

23
Q 
RNA processing in eukaryotes
How it's different from bacteria 
Intron
Exon
Splicing
A

Eukaryotic mRNAs have a pre mRNA form that requires processing into mature mRNA

Coding sequence in structural genes, they’re transcribed but not translated

Coding sequence found in mature mRNA

Removal of introns

24
Q

What is a cap, when is it added, what’s it’s function
What’s a tail, when’s it added what’s its function for
Addition of tails and caps in RNA processing (eukaryotes)

A

A cap is a form of guanosine attached to the 5’ end
Added when pre mRNA is made
It’s function is to be recognized by the cap binding proteins which allow mRNA to exit nucleus and bind to ribosomes

A tail is 100-200 adenine nucleotides added to the 4’ ending . Added after pre mRNA is made
Aids in export of mRNA from nucleus and gives stability to mRNA

25
Q

Self splicing
How they do it
Ribozymes

A

rRNA and RNA.
RNA catalyze removal of intron
An RNA molecule that catalyze a a chemical reaction like self splicing

26
Q

Splicing
Where it happens
Spliceosome
Alternative splicing

A

Removal of introns
Happens at branch site 5’ splice site and 3’ splice site
Removes introns precisely. Made of small nuclear RNA AND proteins
Splicing can occur more than one way to produce different products

27
Q

Genetic code
Codon
What do they do
Degenerate code

A

Sequence of bases in an mRNA molecule
Group of 3 nucleotide bases
They specify a particular amino acid exp. ggc meand glycine

More Than one codon can specify the same amino acid

28
Q

Bacterial mRNA
Where is the ribosomal binding site
What’s the start codon, what does it define
What’s the stop codon aka termination code
How long is a typical amino acid

A 
5' ribosomal binding site
AUG, methionine
Defines the reading frame, or the order I which the codons are read
UAA, UAG, or UGA
A few hundred amino acids long
29
Q

What shifts the reading frame

A

Aiddtion of a nucleotide base which throws off all the other codon

30
Q

Substitution to base in mRNA

A

T is substituted with U

31
Q

tRNA ANTICODON

A

ANTICODON is a three base sequence in a tRNA molecule that is complementary to mRNA, causing them to bind together.
Exp, is the ANTICODON in tRNA is 3’ AAH5’ then its complementary to a 5’ UUC 3’ codon. UUC is for phenylaline, so that tRNA molecule will carry phenylaline.

32
Q

90% of energy in ecoli is used

A

To transcript mRNA into polypeptides

33
Q

Translation requires more components than transcription because the sequence of codons in mRNA must be translated into a sequence of amino acids according to the genetic code

What are four of the components translation requires

A

mRNA
tRNA
RIBOSOMES
TRANSLATION FACTORS

34
Q

Common factors of a tRNA molecule (3)

Different tRNA molecules are encoded by different genes

What they carry is in their name, tRNAser carries serine

A

Cloverleaf structure
ANTICODON
Acceptor stem for amino acid binding

35
Q 
Aminoacyl-tRNA Synthetase 
What it does
How Many are therea
Reactions result in ( 2 names for that product)
Where it attaches
The second genetic code refers to
A

Catalyzes attachment of amino acids to tRNA
There’s one for each of the 20 different amino acids
Reactions result in tRNA with amino acid attached (charged tRNA or amino acid tRNA)
Attaches to the 3’ end

The ability of each aminoacyl- tRNA synthetase to recognize the right tRNA

36
Q

4 steps of aminoacyl tRNA synthetase

A
  1. Specific amino acid and atp bind to aminoacyl tRNA synthetase
  2. the amino acid is activated by the covalent bonding of AMP and a pyrophosphate is released
  3. the correct tRNA binds to the synthetase. The amino acid is covalently attached to the tRNA and amp is released
  4. the charged tRNA is released
37
Q

RIBOSOMES
Nickname for them
Site where what takes place
Prokaryotes have ____ kind of ribosome which____
Eukaryotes have distinct RIBOSOMES in different compartments but right now we’re focusing on ____
Structural differences between prok and euk exploited by antibiotics to inhibit _____

A

Molecular machine
Translation
One kind of ribosome which translates all mRNAs in cytoplasm
Here we’re focused on cytosolic RIBOSOMES
Bacterial RIBOSOMES

38
Q

RIBOSOMES shape determined by
P site
A site
E site

A

Determined by rRNA

Peptidyl site
Aminoacyl site
Exit site

39
Q

Stages of translation
Summary of what happens
3 part Explanation of what happens
Two eukaryotic differences in initiation

A

Initiation, elongation, termination

mRNA first tRNA and ribosomal subunits assemble

mRNA binds to the small ribosomal subunit
Initiator tRNA binds to the start codon in mRNA
Large ribosomal subunit binds

MRNAs have a guanosine cap at 5’ end instead of a ribosomal binding cap

Position of the start codon can vary more. Many times first AUG codon is used as the start codon

40
Q

Step 2
Summary
Step by step (4)

A

Synthesis starts from start codon to stop codon

Aminoacyl tRNA brings a new amino acid to the a site

Binding occurs due to codon/ ANTICODON recognition

Peptide bond is formed between the amino acid at the a site and the growing polypeptide chain

Movement (translocation) of the ribosome toward the 3’ end of the mRNA by one codon

41
Q

Termination
What happens
How many stop codons/ what are they
Release factors

A

When a stop codon is found in the a site, translation ends
There are 3 stop codons, UUA UAG UGA

These are what recognize the stop codon and bind to it at the a site

Biology (11 decks)

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