BY Chapter 9

The genetic code consists of __ possible codons that specify amino acids.

64

Types of Mutations:

Base pair substitutions, insertions, deletions

T or F: 1 tRNA comes during elongation.

False! 2

If a mutation arises in a _____, it may be passed on to offspring.

Gamete

A unit of information for a heritable trait

Gene

A multistep process including transcription and translation by which genetic information encoded by a gene is converted into a structural or functional part of a cell

Gene Expression

A linear stretch of DNA that specifies the sequence of amino acids in a polypeptide is called a(n)

Gene.

3 stages of translation:

Initiation, Elongation, Termination

In correct order, the three stages of translation are...

Initiation, chain elongation, and termination.

Frameshift Mutations:

Insertion and Deletion

Non - coding portions, ___, are cut out.

Introns

The portion of the DNA molecule that is not translated and is a noncoding portion of DNA is composed of...

Introns.

Termination:

Release of the finished polypeptide

What is the site of protein synthesis?

Ribosomes

rRNA:

Major component of ribosomes upon which polypeptides are assembled

Elongation:

Makes the chain of polypeptides

The form of RNA that carries the code from DNA to the site of protein assembly is called:

Messenger RNA

__________ molecules carry protein-assembly instructions from the nucleus to the cytoplasm.

Messenger RNA

What are the three classes of RNA?

Messenger RNA, Ribosomal RNA, and Transfer RNA

Initiation:

The ribosomal subunits join around the mRNA strand and the mRNA and tRNA undergo base pair matching

A gene mutation:

is a change in the nucleotide sequence of DNA, may occur spontaneously, may occur as a result of environmental agents

Translation:

mRNA leaves the nucleus and finds a ribosome. mRNA is decoded into a sequence of amino acids, resulting in a polypeptide chain that folds into a protein.

Transcription...

occurs during the synthesis of any type of RNA from a DNA template.

Transcription starts at a region of DNA called a(n)

promoter.

If the DNA triplets are ATG-CGT, the mRNA codons are...

UAC-GCA.

Which substance is found in RNA but not in DNA?

Uracil

The RNA molecule is made up of how many strands?

1

How many codons of the code serve to stop protein synthesis?

3

The genetic code is made up of units consisting of how many nucleotides?

3

The end of RNA that is not capped contains what?

A "Poly A" signal that helps with stopping translation

Unlike DNA Replication, in Transcription...

A single strand is produced Only a small stretch is used as a template RNA Polymerase catalyzes rather than DNA Polymerase

What is always the "start" codon?

AUG

Uracil will pair with _.

Adenine

Each codon stands for a specific ___.

Amino Acid

Each gene is a linear stretch of DNA that codes for the specific assembly of ___ into a ___

Amino Acids; Protein

Before leaving the nucleus, the RNA molecule:

Becomes capped, is released from the STOP signal, is stripped of its introns

Before RNA leaves the nucleus, one end is ___.

Capped with a specific signal that is involved in translation.

mRNA:

Carries protein building instruction from DNA

DNA is transcribed in three letter sequences known as ___.

Codons

Anticodon:

Complementary to a mRNA codon; tRNA has them

Where does translation occur?

Cytoplasm

Transcription:

DNA is copied into a new code to produce mRNA. It occurs in the nucleus. mRNA moves into the cytoplasm. Synthesizes new molecules by base-pairing.

tRNA:

Delivers the appropriate amino acids to the ribosome for assembly into a protein

Coding portions, ___, are left in.

Exons

Which of the following agents is a known cause of mutations?

Nonionizing radiation, ionizing radiation, and chemicals.

RNA transcription occurs in the:

Nucleus

Transcription begins when RNA Polymerase binds to a ____.

Promoter Region

____ transcribes DNA into RNA.

RNA Polymerase

Two steps that create all proteins:

Transcription and Translation

T or F: Like DNA replication, nucleotides are added in 5' to 3' direction in transcription.

True

In RNA, T is replaced with __.

U

Frameshift mutations may involve...

addition or deletion of one or more base pairs.

Which of the following carries amino acids to ribosomes, where amino acids are linked into the primary structure of a polypeptide?

tRNA