Termination and translations Flashcards

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0
Q

RNA is the________between genes and proteins for which they code

A

Intermediate

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1
Q

Transcription

A

The synthesis of RNA under the direction of DNA

Produces mRNA-messenger RNA

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2
Q

Translation

A

Is the synthesis of a polypeptide which occurs under the direction of mRNA

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3
Q

Ribosomes

A

Are the sites of translation

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4
Q

DNA template strand

A

A T and CG

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5
Q

Transcription mRNA strand

Codon

A

UA and GC

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6
Q

Translation proteins

amino acid Strand

A

Specific proteins

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7
Q

Eukaryotic cells ________ RNA after transcription.

A

Modify

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8
Q

Enzymes in the eukaryotic nucleus modify pre-mRNA before

A

The genetic messages are dispatched to the cytoplasm

Some interior parts of the molecule are cut out and the other parts spliced together

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9
Q

Most eukaryotic genes and their RNA transcript have long non-coding stretches of…

A

Nucleotides that lie between coding regions

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10
Q

Intervening sequences or Intron’s

A

Non-coding regions

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11
Q

Exons

A

Other region then intron

it’s called Exon because they are eventually expressed, usually translated into amino acid sequences

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12
Q

RNA splicing

A

Removes Intron’s and joins exons creating an mRNA molecule with the continuous coding sequence

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13
Q

Alternative RNA splicing

A

Some genes can encode more than one kind of polypeptide depending on which segments are treated as exons during RNA splicing

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14
Q

Transfer RNA a.k.a. tRNA

A

A cell translates an mRNA message into protein with the help of tRNA
Molecules of tRNA are not identical

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15
Q

Each TRNA carriers A specific amino acid on one end and an ______ on the other end ;the anti-codon base-pairs with a complementary_______on mRNA

A

Anticodon

Codon

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16
Q

Ribosomes facilitate specific coupling of _______ anti-codons with_______codons in protein synthesis

A

TRNA

mRNA

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17
Q

To ribosomal subunits (large and small) are made of two things

A

Proteins and ribosomal RNA or a.k.a. RRNA

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18
Q

A ribosome has three binding sites for tRNA

A

P site
A site
E site

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19
Q

P site

A

Holds the tRNA that carries the growing polypeptide chain

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20
Q

A site

A

Holds the tRNA that carries the next amino acid to be added to the chain

21
Q

E site

A

The exit site where discharged tRNAs leave the ribosome

22
Q

The initiation stage of translation

A

Brings together mRNA, tRNA with the first amino acid, and the two ribosomal subunits

23
Q

steps in the initiation stage

A

A small ribosomal subunits bind with mRNA and the special initiator tRNA
Next the small subunit moves along the mRNA until it reaches the start codon AUG

24
Q

During elongation stage

A

Amino acids are added one by one to the preceding amino acid

25
Q

Termination occurs when

A

A Stop codon in the mRNA reaches the A site of the ribosome
The A site accepts the protein called a release factor
the release factor causes the addition of a water molecule instead of an amino acid

26
Q

Often translation is not sufficient to make a

A

Functional protein

27
Q

Polypeptide chains are modified _____ translation

A

After

28
Q

Completed proteins are targeted to ______ sites in the cell

A

Specific

29
Q

During and after synthesis

A

A polypeptide chain spontaneously coils and folds into a three-dimensional shape

30
Q

Proteins may also require

A

post translational modifications before doing their job

31
Q

Two populations of ribosomes are evident in cells

A

Free ribosomes in The cytosol and

bound ribosomes attached to the ER

32
Q

Free ribosomes

A

Mostly synthesize proteins that function in the cytosol

33
Q

Mutations

A

Changes in the genetic material of a cell or virus

34
Q

Point mutations

A

Are chemical changes in just one base pair

35
Q

The change of a single nucleotide in a DNA strand can lead to

A

The production of an abnormal protein

36
Q

Point mutations within a gene can be divided into two general categories

A

Base pair substitutions

Base pair insertions or deletions

37
Q

Base pair substitution

A

Replaces one nucleotide and it’s partner with another pair of nucleotides

38
Q

Silent mutation

A

Have no affect on the Amino acid produced by a codon because of redundancy in the genetic code

39
Q

Missense mutations

A

Still code for an amino acid but not necessarily the right amino acid

40
Q

Nonsense mutation

A

Change an amino acid codon into a stop codon nearly always leading to a non-functional protein

41
Q

Types of substitutions

A

Missense and nonsense mutations

42
Q

Insertions and deletions

A

Are additions or losses of nucleotide pairs in a gene which is more damaging
insertion or deletion of nucleotides may alter the reading frame producing a frameshift mutation

43
Q

Mutagens

A

Physical or chemical agents that can cause mutations

44
Q

Spontaneous mutations can occur during

A

DNA replication or recombination or repair

45
Q

While gene expression differs among the domains of life the concept of a gene is…

A

Universal

46
Q

Archaea

A

Prokaryotes but share many features of gene expression with eukaryotes

47
Q

Bacteria and Eukarya differ in

A

Their Rna polymerases and termination of transcription and ribosomes
Archaea tend to resemble you Eukarya in these respects

48
Q

The idea of the gene itself is a unifying concept of life

A

discrete unit of inheritance
Region of specific nucleotide sequence in a chromosome
DNA sequence that codes for a specific polypeptide chain

49
Q

Gene can be defined as

A

A region of DNA that can be expressed to produce a final functional product which is either a polypeptide or an RNA molecule