BSCI222 Genetics Unit Two (copy)

centromere

The region of a chromosome where the two sister chromatids are joined together, playing a crucial role during cell division by facilitating the proper segregation of chromosomes.

euchromatin

A lightly packed form of chromatin that is actively involved in transcription, allowing for gene expression and accessibility to DNA. (Crosses over)

heterochromatin

A tightly packed form of DNA, which is generally transcriptionally inactive, playing a role in maintaining chromosome structure and regulating gene expression.(doesn’t cross over)

What is the purpose of RNA cleavage?

Dividing a long r RNA into smaller functions units

telomere

The end region of a chromosome, consisting of repetitive nucleotide sequences, which protects chromosome ends from deterioration and prevents fusion with neighboring chromosomes.

semi-conservative synthesis

the mechanism by which DNA replicates itself. In this process, each of the two strands of the original DNA molecule serves as a template for the formation of a new complementary strand.

Helicase (Prokaryotes)

an enzyme that unwinds the double-stranded DNA helix during DNA replication to allow DNA polymerase to synthesize complementary strands

Gyrase

(prokaryotes) managing the physical structure of the DNA helix as it is unwound

Primase

(prokaryotes) type of RNA polymerase that creates a primer

DNA Polymerase I

(prokaryotes) removes RNA primers and replaces them with DNA nucleotides to complete the strand

DNA Polymerase III

(prokaryotes) primary enzyme for DNA replication

Ligase

(Eukaryotes) acts as the molecular "glue" that creates a continuous DNA strand by joining separate fragments together

Helicase (Eukaryotes)

a critical enzyme complex responsible for initiating and maintaining the unwinding of the DNA double helix during replication

Topoisomerase

(eukaryotic) relieves the strain from unwinding

DNA pol alpha

(eukaryotic) Initiates synthesis with a primase sub-unit

DNA pol delta

(eukaryotic) primary enzyme responsible for synthesizing the lagging strand

DNA pol epsilon

(eukaryotic) main enzyme responsible for synthesizing the leading strand

FEN1

(eukaryotic) specialized enzyme essential for completing the synthesis of the lagging strand, primary role is to process the "flaps" created during the removal of RNA primers

DNA Ligase

(Prokaryotic) functions as molecular "glue" that creates a continuous DNA strand by joining separate fragments together

mRNA

carries the genetic code from the nucleus to the ribosome

tRNA

the physical link between the mRNA sequence and the amino acid sequence by carrying specific amino acids to the ribosome during translation

rRNA

associates with a set of proteins to form ribosomes

snRNA

Small RNA molecules found within the nucleus of eukaryotic cells making up the spliceosome

RNA Polymerase I

transcribes genes for rRNA

RNA Polymerase II

transcribes protein-coding genes for mRNA

RNA Polymerase III

transcribes tRNA

structural genes

encode proteins that are directly involved in the physical structure of the cell, producing enzymes or transporting proteins

regulatory genes

encode proteins/RNA molecules, producing DNA-binding proteins (activators/inhibitors)

positive transcriptional control

regulatory protein acts as an activator, recruiting RNA polymerase

negative transcriptional control

the regulatory protein acts as a repressor blocking RNA polymerase

Helix-turn-Helix protein

type of DNA binding protein with two alpha helices where one helix fits into the DNA groove to recognize a base sequence

Zinc finger protein

type of DNA binding protein that contains a loop of amino acids reaching into groove of DNA

Leucine zipper proteins

type of DNA binding protein formed by two alpha helices that zip together where two arms grip the DNA backbone and groove

inducible operon

operon that’s off from repressor protein and must be turned on by an inducer (lac operon)

repressor operon

operon that’s usually on and gets turned off by a co-repressor (trp operon)

co-repressor

molecule that binds to a repressor protein to switch it into active state

attenuation

prokaryotic gene regulation that causes transcription to terminate prematurely before the structural genes are reached

histone modification

type of epigenetic regulation where a chemical group is added to the tail of histone proteins

DNA Methylation

type of epigenetic regulation where a methyl group is added to a cytosine base of a DNA molecule

insulators (transcript. regulation)

DNA sequences that function as boundary elements by blocking enhancers

TADs (transcript. regulation)

large loops of DNA where sequences within the loop interact frequently with each other

transcriptional stalling

regulatory mechanism in eukaryotes where RNA polymerase II initiates transcription and produces a short RNA strand, but then stops or "stalls" just downstream of the promoter

miRNAs

type of regulatory RNA that inhibit translation

siRNAs

type of regulatory RNA that lead to direct cleavage and degradation of target mRNA sequence

RNAi

A biological process where small RNA molecules (miRNAs and siRNAs) inhibit gene expression or translation

piRNA

small group of RNAs that regulate gene expression and prevent mutations

genetic imprinting

epigenetic phenomenon where certain genes are expressed in a parent-of-origin-specific manner

cis configuration

dominant alleles for two different genes are located on the same homologous chromosome

trans configuration

a dominant allele for one gene and a recessive allele for another are on the same chromosome

Holoenzyme

Part of prokaryotic transcription that initiates transcription through unwinding DNA by conformational shift

Rho dependent

Prokaryotic termination where Rho binds to a rut site moving in 5,→ 3’ direction pausing RNA polymerase

Rho independent

Prokaryotic termination where sequences on RNA form hairpin

Polycistronic RNA

bacterial genes at one promoter causing one long RNA for transcription

Basal transcription factors

Required for RNA polymerase to bind for eukaryotic transcription

(Eukaryotic Transcription) What are ways for DNA to be loosened on nucleoside

Histone acetylation and histone demethylation

Rat1 enzyme

Recruited during eukaryotic transcription to cut RNA a and release the preMRNA

Polyadenylation

Type of RNA processing that adds a 3’ polyA tail

Capping

Type of RNA processing that adds a 5’ cap

Splicing

Type of RNA processing that removes introns from mRNA and joins exons

Exons

Sequences that contain information for translation

Alternative Splicing

Multiple proteins to create different mRNAS during RNA processing

tRNA processing utilizes

Base modifications

rRNA processing

Multiple rRNAS transcribed together then processed

1° Protein Sequence

Amino acid sequence

2° Protein Sequence

Hydrogen bonding of backbone with beta sheet or alpha helices

3°/4° Protein Structure

R group interactions forming structure

Ribosomal small subunit

mRNA binding protein

Ribosomal large subunit

Enzymatic

Shine Delgarno Sequence

Where ribosomes bind to for prokaryotic translation

Kozak sequence

Where ribosomes bind for eukaryotic translation

Pribnow Box

Promoter sequence for transcription in prokaryotes at (-35/-10bp)

Tata Box

Promoter binding spot for eukaryotic transcription (-25bp)

Introns

Nucleotide group not containing amino acid information

What does tRNA have that is complementary to the mRNA

Anticodons

What’s the difference between eukaryotic and prokaryotic initiation of recruit ribosomes

Prokaryotic uses sequence information to recruit ribosome while eukaryotes use 5’ cap

Promoter

Section on operon where rna polymerase binds

operator

Section on operon where inducer or repressed binds

inducer

Molecules that bind to repressor or or activator to regulate transcription (on or off)

Activator

Protein that Binds to DNA to promote transcription.

Repressor

Proteins that bind to operator to turn genes off

If tryptophan is Low the ribosome

Stalls and forms antiterminator (hairpin) which halts translation but keeps transcription

If tryptophan is high ribosome,

Continues and forms a strong hairpin to stop transcription

What brings DNA to promoter by bending

CAP+cAMP

Histone methyl transferase (HMT)

adds methyl groups

Histone demethylase (HDM)

Removes methyl groups

Histone acetylene transferase (HAT)

Adds acetyl group

Histone deacetylaste (HDAC)

Removes acetyl groups

Topologically Associated domains (TADS)

Transcriptionally active loops of DNA

Transcriptional stalling

Transcription starts but RNA polymerase stalls

Riboswitch

(Negative feedback) Stem loop formed on 5’ end blocking Shine Dalgarno, preventing ribosome binding

Anti sense RNA (sRNA)

Non coding regulatory genes that’s reverse complement of mRNA , blocking translation

CRISPR

prokaryotic defense against foreign DNA using Cas protein to degrade DNA sequences

microRNAS (miRNA)

Double stranded RNA molecules made by cutting hairpin RNA with Dicer ; eukaryotes transcribe this complementary , with Argonaut proteins form RISC complex to inhibit translation

lncRNA (long non coding RNA)

Regulatory genes that get capped but not translated, making mRNA less effective

siRNA (small interfering RNA)

Combines with Ago proteins to form RISC that cleaves complementary mRNA from viral DNA, initiating transcription silencing of specific genes

Genomic imprinting

When alleles are silenced depending on which parent they come from

Telocentric

Joins chromatids at tips

Acrocentric

Joins chromatids near tips (short p, long q)

Sub meta centric

Joins chromatids near center

Meta centric

Joins chromatids at center