BIO 181 GCU Quiz 7

What are two chemical components of chromosomes?

DNA and Proteins

Helices

unwinds parental double helix at replication forks

Replication Fork

A Y-shaped region on a replicating DNA molecule where new strands are growing.

Topoisomerase

corrects "overwinding" ahead of replication forks by breaking, swiveling, and rejoining DNA strands

Primase

synthesizes an RNA primer at 5' end of leading strand and at 5' end of each Okazaki fragment of lagging strand

DNA Pol III

adds nucleotides to an RNA primer or a pre-existing DNA strand

Using parental DNA as a template, synthesizes new DNA strand by adds nucleotides to an RNA primer or a pre-existing DNA strand

DNA Pol I

Removes RNA nucleotides of primer from 5' end and replaces them with DNA nucleotides

DNA ligase

joins Okazaki fragments of lagging strand; on leading strand, joins 3' end of DNA that replaces primer to rest of leading strand DNA

single strand binding proteins

bind to and stabilize single-stranded DNA

exonuclease

an enzyme that removes successive nucleotides from the end of a polynucleotide molecule

endonuclease

group of enzymes that break the phosphodiester bond present within the polynucleotide chain of a DNA molecule

Telomerase

catalyzes the lengthening of telomeres in germ cells

Antiparallel Elongation

each strand of DNA faces in an opposite direction

Lagging Strand

A discontinuously synthesized DNA strand that elongates by means of Okazaki fragments, each synthesized in a 5' to 3' direction away from the replication fork.

How can DNA transform bacteria?

occurs after restriction digest and ligation and transfers newly made plasmids to bacteria

Limitations for DNA polymerase

creates problems for the linear

Chargaff's Rule

A=T and C=G

DNA double helix

the two DNA strands run antiparallel

Franklin's X-ray crystallographic images of DNA

enabled Watson to deduce that DNA was helical

Chromatin

Clusters of DNA, RNA, and proteins in the nucleus of a cell

Heterochromatin

highly condensed chromatin

Euchromatin

loosely packed chromatin

Transcription

(genetics) the organic process whereby the DNA sequence in a gene is copied into mRNA

Translation

Process by which mRNA is decoded and a protein is produced

RNA Polymerase

Enzyme similar to DNA polymerase that binds to DNA and separates the DNA strands during transcription

TATA box

crucial promoter DNA sequence

tRNA

transfer RNA; type of RNA that carries amino acids to the ribosome

rRNA

ribosomal RNA; type of RNA that makes up part of the ribosome

mRNA

messenger RNA

DNA polymerase

principle enzyme involved in DNA replication

Coding Nucleotides

exons

Noncoding Nucleotides

introns

Ribozyme

a type of RNA that can act as an enzyme

Spliceosome catalytic activity

The RNAs of the spliceosome catalyze the splicing reaction

Start Codon

AUG

Stop Codon

UAA, UAG, UGA

Central Dogma

DNA -> RNA -> Protein

Promoter

region of DNA that indicates to an enzyme where to bind to make RNA

Introns

sequence of DNA that is not involved in coding for a protein

Exons

Coding segments of eukaryotic DNA.

Mutations

a random error in gene replication that leads to a change

alternative splicing

Post-translational RNA modification process in which some exons are removed or joined in various combinations.

nonsense mutation

A mutation that changes an amino acid codon to one of the three stop codons, resulting in a shorter and usually nonfunctional protein.

frameshift mutation

mutation that shifts the "reading" frame of the genetic message by inserting or deleting a nucleotide

Missense

a mutation that changes one amino acid

tryptophan operon

repressible operon---when trp is absent, the repressor is inactive-----when trp is present and there is enough of it, the trp binds to the repressor and activates it to stop producing

lactose operon

contains three structural genes, each coding for an enzyme that aids in lactose metabolism

repressors

proteins that block transcription

inducers

drugs that act on the liver to increase rates of drug metabolism

activator

a protein that binds to DNA and stimulates transcription of a gene

terminator

In prokaryotes, a special sequence of nucleotides in DNA that marks the end of a gene.

Nucleosome

repeating subunit of chromatin fibers, consisting of DNA coiled around histones

Epigenetic inheritance

inheritance of traits transmitted by mechanisms that do not involve the nucleotide sequence

Ras Protein function

G protein that relays signal from growth factor on plasma membrane

Xeroderma pigmentosum

Mutated single strand nucleotide excision repair gene, which prevents repair of thymidine dimers.; Dry skin w/ melanoma and other cancers ("children of the night").

CML (chronic myelogenous leukemia)

long chromosome 22 and short chromosome 9

malignant tumor

A cancerous tumor that is invasive enough to impair the functions of one or more organs.

Control of gene expression

Cells control amount and timing of protein (enzyme) production

Genes: Promoter Region

An upstream binding region for the enzyme RNA polymerase to begin the encoding process (Transcription starts here)

Can be referred to as the 'TATA' box and tells the free floating nucleotides to bind with the DNA strand that is to be transcribed

Eukaryotes

Cells that contain nuclei

prokaryotic

No nucleus

Three components of a nucleotide

phosphate, sugar, base

Watson and Crick

Developed the double helix model of DNA.

nucleic acids are polymers called

polynucleotides

each polynucleotide is made of monomers called

nucleotides

nucleoside consists of

base and sugar

more evidence for DNA as genetic material came from studies of ____

viruses that infect bacteria

bacteriophages (or phages)

viruses that infect bacteria

a virus is

DNA enclosed by a protective coat often simply protein

Hershey and Chase showed what

DNA is the genetic material of a phage known as T2

If aDrosophilafemale has a homozygous mutation for a maternal effect gene, ______.

All of her offspring will show the mutant phenotype, regardless of their genotype

Which of the following sets of materials are required by both eukaryotes and prokaryotes for replication?

double-stranded DNA, four kinds of dNTPs, primers, origins

The lactose operon is likely to be transcribed when:

when there is more glucose than lactose

An Okazaki fragment has which of the following arrangements?

5' RNA nucleotides, DNA nucleotides 3'.

Embryonic lethal mutations result in:

Mendelian diseases

In humans, identical twins are possible because:

early blastomeres can form a complete embryo if isolated

The role of a metabolite that controls a repressible operon is to:

Bind to the repressor protein and activate it.

Which of the following, when taken up by the cell, binds to the repressor so that the repressor no longer binds to the operator?

Inducer

The formation of the fertilization membrane requires an increase in the availability of:

Calcium Ions