Genetics Exam 2

Karyotype

An individual’s complete set of chromosomes.

P

The short arm of a chromosome.

Q

The long arm of a chromosome.

Independently

Genes assort ______ if they are on different chromosomes or far apart on the same chromosome.

Linkage

Gene show ______ if they are on the same chromosome and close together.

Crossing over

If genes are too close together on the same chromosome, ______ ____ cannot take place (2 words).

Recombination

______ during meiosis sorts alleles into new combinations

Parental

Nonrecombinant gametes

Recombinant

Nonparental gametes

Parental

Without crossing over, 100% of offspring will be _______

Complete Linkage

Occurs when there is no recombination and no crossing over

Prophase 1

Crossing over in which phase of meiosis creates recombinants between linked genes?

Recombination frequency

Number of recombinant progeny/total number of progeny x 100

Cis

Two wild-type alleles on one homolog and two recessive on the other (coupling)

Trans

One wild type and one recessive on each homolog (repulsion)

True

True or False? A+G = T+C

False

True or False? A+T = G+C

True

True or False? A=T and G=C

44%

If the GC content of DNA is 56%, what is the AT content?

DNA

Evidence supports the hypothesis that ___ is the transformative and hereditary material

Polymer

Made up of repeating monomeric units

Nitrogenous base, phosphate group, sugar

DNA consists of… (3 terms)

5

Phosphate group is located at the ___ prime carbon

1

Nitrogenous base is located at the ___ prime carbon

Negative

Phosphate group gives DNA a ______ charge

2

Ribose contains an OH group at the ____ prime carbon

Pyrimidines

Thymine, cytosine, and uracil are….

Purines

Adenine and guanine are…

Complementary

DNA strands are _____ to each other

Hydrogen bonds

_________ _____ between paired nitrogenous bases hold the two strands together

Stranded, parallel

DNA strands are double _____ and anti _______

Euchromatin

Type of chromatin that is very loose and therefore more expressed

Heterochromatin

Type of chromatin that is very tight and less expressed.

200

In total, there are about ____ base pairs (bp) associated with each nucleosome

Epigenetics

Alterations of chromatin structure that are passed onto descendent cells.

Methylation

Can cause less expression by attaching methyl groups to histone tails

acetylation

Cause cause more expression by attaching acetyl groups to a histone tail

Centromeres

Located in the middle of chromosomes, composed of mostly heterochromatin, have no specific sequence, cause epigenetic changes in chromatin

Telomeres

Located at the ends of chromosomes, contain repetitive and specific sequences

Origin recognition complex

Backronym of ORC

Semiconservative

DNA replication is ________, meaning it separates strands and makes copies on said strands.

Leading strand

The strand where replication is continuous

Lagging strand

The strand where replication is discontinuous

Okazaki fragments

Short fragments of DNA produced by discontinuous synthesis

DNA helicase

Enzyme that binds to the lagging strand template at each replication fork and moves in the 5’—>3’ direction, breaking hydrogen bonds and moving the replication fork

Single stranded binding proteins

Proteins that stabilize the exposed single-stranded DNA

DNA gyrase

Enzyme that relieves strain ahead of the replication fork

Primase

Enzyme that synthesizes short stretches of RNA nucleotides, providing a 3’ OH group to which DNA polymerase can add DNA nucleotides

DNA polymerase III

Enzyme that catalyzes addition of DNA, matches strands in complementary manner.

DNA Polymerase I

Removes primers and puts nucleotides together

Licensing factor

Detects where starting point is for DNA replication. Must be present for origin identification. After replication, it is inactive and cannot enter the cytoplasm

Telomerase

Enzyme that can extend the ends of chromosomes in particular cells. Identifies replicating sequences and extends chromosomes

RNA

A molecule that is generally produced as a single stranded molecule, but can fold into complex 3-D structures

RRNA

RNA used for protein synthesis

MRNA

Coding instructions for proteins

Pre-mRNAs

Immediate products of transcription in eukaryotes

TRNA

Linking between mRNA and amino acids

Transcription

Synthesis of RNA from a DNA template. When cells take information from DNA and put it into RNA

Template strand and coding strand

The names of the strands used in transcription

3 5

The template strand for transcription is oriented from _’ to _’

Promotor

Included in transcription, indicates which of the two strands is the template and the direction of transcription and the transcription start site

RNA-coding region

Copied into RNA, codes for RNA

Terminator

Signal to stop transcription

Sigma factor

Aids in binding of RNA polymerase as promotor and initiation

Consensus sequence

Common nucleotides in a stretch, might be functionally important

Y

Letter used in consensus sequences; represents either pyrimidine

R

Letter used in consensus sequences; represents either purine

C/G

Letter used in consensus sequence; represents any two nucleotides that are equally common

N

Letter used in consensus sequences; represents no common nucleotides in a stretch

False

True or False? You need a primer for RNA polymerase to start.

Downstream

Transcription bubble moves ______ as RNA polymerase moves

Hairpin, uracils

Transcription terminates when inverted repeats form a ______ followed by a string of ______

exon

A coding region for a protein, expressed in pre-mRNA

intron

Processed out of the mature mRNA, inserted and must be removed

5’ cap

Adds 1 modified guanine to 5’ end of the pre-mRNA, also adds methyl groups. Increases stability of the mRNA.

Poly(A)tail

Added to 3 end of mRNA after transcription. Functions in stability, export from nucleus and ribosomal attachment

Splice sites

Signal exon/intron boundaries, necessary to add an “A” nucleotide at the branch point. One added at both 5’ and 3’ ends of RNA.

Alternative splicing

Can produce different proteins from the same DNA sequence. Produces different mRNAs from a single pre-mRNA