Tarleton Genetics 3303 Dr. Pfau FINAL EXAM

Where do sister chromatids come from?

Homologous or non-homologous chromosomes?

DNA replication, identical copies

Homologous chromosomes: (same size, shape, and gene. one from mom/dad= inheritance)

Gene

A specific Stretch of DNA (only a portion) containing the info to produce an RNA molecule, which may or may not be used to make a polypeptide, which may or may not be a protein.

Purines have ___ carbon rings and Pyrimidines have ___ carbon rings. which nitrogenous bases fall into each category?

Purines = 2 carbon rings and their nitrogenous bases are A & G

Pyrimidines = 1 carbon ring and their nitrogenous bases are C & T

Name all 4 non-functional genetic sequences and describe each.

Pseudogenes: from ancestors

Viral Sequences: virus inserted into DNA

Repetitive Sequences: 3' CAG 5' ---> 3' CAAAGGG 5'

Transcribed Elements: "copy/paste" anywhere

What are the 3 roles of DNA as a hereditary material?

Replication: (not 100%) ---> mutations

Information Content

Ability to change/adapt to environment

Variations of one gene are known as

Alleles

the Packaging of DNA is Hierarchical. The double stranded DNA strand is wrapped around proteins known as _____. These "beads on a string" are referred to as ________.

Histones

Nucleosomes

Continuous Variation

complex traits

ex: hair color in humans

Discontinuous variation

simple traits

ex: dog lab coat colors

which DNA strand is Identical to

3' CAGTCCAGATC 5' ?

5' CTAGACCTGAC 3'

which DNA strand is complementary to

3' CAGTCCAGATC 5'

5' GTCAGGTCTAG 3'

What kind of cells have introns and exons?

Eukaryotic Cells ONLY

intron

A stretch of DNA within a gene that does not contain info to be translated, "interfering", "no purpose"

exon

expressed gene, "good stuff"

loci and/or locus

A specific location on a chromosome

Hydrogen bonds

the bonds between two complementary strands of DNA

The bonds that link nucleotides on a single strand of DNA are

Phosphodiester Bonds (covalent)

Heterochromatin

tightly packaged DNA

Euchromatin

loosely packaged DNA

Purines pair with _____

pyrimidines

A strand of DNA contains 17% Thymine, what is the amount of Guanine?

33%

Karyotype

A representation of chromosomes in the cell, large to small except x/y

How many Hydrogen bonds are in the DNA below?

3' CATTGCCTA 5'

5' CTAACGGAT 3'

22

A cell contains 3 unreplicated chromosomes. Following DNA replication, how many replicated chromosomes will it contain?

3

Nuclear Genome

linear, intron

Organelle Genome (Mitochondria/Chloroplast)

Circular, Endosymbiosis

Viral Genome

RNA/DNA, Circular/Linear

Prokaryotic Genome

Circular, Plasmids

mRNA

"Messenger RNA"

sends information to ribosomes

tRNA

"Transfer RNA"

Brings Amino Acids for translation

rRNA

regulates gene expression

How is DNA faithfully replicated?

template strand

double-stranded

Telocentric Chromosome

Centromere located at end

Acro-Centric Chromosome

Centromere located close to end

Sub-Metacentric Chromosome

Centromere located off centered

Metacentric Chromosome

Centromere in the middle

T/F: Sex chromosomes are either X or Y

False

what are the 2 ways that mutations can occur?

SNP's: Single Nucleotide Polymorphism

Indels: INsertion, DEletion

Where do Kinetochores attach to?

the centromere

what are Base pairs (bp)

how DNA is measured

A cell contains 5 unreplicated chromosomes, immediately after DNA replication how many strands of DNA would the cell contain?

10

list the 3 functional regions of a gene and describe them

promoter: start region

Transcribed Region: Transcription

Termination: Stop region

List the 4 ways genomes can differ among species

Number of Chromosomes

Amount of DNA

Format of DNA

Organization of genes

what usually has the most DNA?

Nucleus

What type of chromosomes contain different versions of the same genes?

Homologous Chromosomes

The only words used to describe chromosomes are?

Homologous

non-Homologous

Why must the expression of genes be regulated?

Different genes must be regulated at different times, locations, and quantities (genes get turned on and off)

Compare and contrast DNA and RNA

During the process of transcription, what enzyme adds nucleotides?

RNA polymerase

the genetic code is nearly ____,_____, with ____ codons

universal

redundant

64 codons

What monomers make up proteins?

What bonds link monomers together?

Amino Acids

Peptide bonds

list the components of a ribosome and there function

A site: arrival of tRNA P

P site: paring of Amino Acids

E site: Exit of empty tRNA

In the presence of lactose, a lac operon would be ______. This process occurs in _____ cells.

Transcribed

Eukaryotic Cells

In a diploid cell, how many genotypes are possible in the expression of 2 genes each with 2 alleles?

9

mRNA

contains information to make proteins

rRNA

the structural components of the site of translation

tRNA

clover shaped, transfers amino acids during translation

scRNA

found in cytoplasm, regulates gene expression

snRNA

found in nucleus, makes modifications to mRNA

What determines the function of a protein?

its shape

A specific amino acids sequence describes ____ structure of a protein

primary

Following transcription, the strand of mRNA is identical to ____

non-template

what produces alleles? list the 4 possible effects

Mutations

1) normal protein

2) Protein not functional

3) Different Protein Function

4) No protein produced

what are the components of an Amino Acid

Central Carbon

Hydrogen

Amino Group

Side Carbon

Carboxylic Acid group

Mutant Allele

Uncommon variant often the result of mutation in wild type allele

wildtype allele

most frequent allele associated with the common phenotype

what binds to the promoter genes to regulate gene expression?

activators

repressors

effector molecules

molecules that can bind to transcription factors

steps of transcription and translation

initiation, elongation, termination

name the 3 stop codons

UAA

UAG

UGA

effector molecule

stimulus that regulates transcription factors, transcription factors regulate genes

Norm of Reaction

One genotype produces a wide range of phenotypes

Penetrance

The Proportion of Individuals in which the genotype is expressed

Variable Expressivity

the degree to which a trait is expressed

environmental influences

Phenotypic variation due to factors such as sun and heat

Epigenetics

the addition of molecules to DNA

Polymorphism

Existence of variation

incomplete/partial dominance

Heterozygous phenotype is intermediate of its homozygous.

ex:

LDLR gene, cholesterol

L/L = normal

L/l = moderate

l/l = high

complete dominance/recessiveness

Heterozygous phenotype is identical to one homozygous

ex:

huntingtin gene

MC1R gene (hair color)

Codominance

Heterozygous phenotype is a combo of both homozygotes

ex:

blood type

Relative Allelic interaction

Environmental conditions affect gene expression

ex:

Beta-globulin gene

sickle cell anemia

genes in different pathways

expression of one gene does not affect the expression of others

ex:

corn snake colors

Epistasis

expression of a gene affects the expression of other genes "down stream"

ex:

dog lab coat colors

X and Y linked genes

genes found on either the X or Y chromosome

ex:

X-linked = opsin gene (colorblind)

Y-linked = SRY gene

where do you get Mitochondrial genes from?

mom ONLY

What are two fundamental mechanisms for inheritance?

DNA replication

Cell Division

How many origins of Genetic Diversity are there? list them

2

Mutations

Sex

Reproduction

Production of new cells/organisms

Sex

Production of genetic diversity by recombining from more than one source

sexual reproduction

Reproduction with sex

(Meiosis/Union of Gametes)

asexual reproduction

Reproduction without sex

(Binary Fission/Mitosis)

Helicase

unzipping of DNA

"separates"

Topoisomerase

Relieves tension on DNA Strand

Single-Stranded Binding Proteins

Prevents the rejoining of DNA strands

Primase

Adds RNA primer

DNA polymerase

Adds nucleotides complementary to template strand

Ligase

joins Okazaki fragments

Telomerase

completely replicates DNA ends = Telomeres

(located in gametic cells)

What are Okazaki fragments?

Short lengths of single-stranded DNA made on the lagging strand.

Semi-discontinuous

lagging strand