Week 11 - Gene Expression

Question 1

Gene Expression/Gene Regulation

Answer 1

The process of turning genes on or off and controlling how much gene product (like RNA or protein) is made. Regulation can occur at multiple levels: transcriptional, post-transcriptional, translational, and post-translational.

Question 2

Transcription

Answer 2

The first step of gene expression where an RNA molecule is synthesized from a DNA template by RNA polymerase.

Question 3

Housekeeping Genes/Ubiquitously Expressed Genes

Answer 3

Genes required for basic cellular function and expressed in nearly all cells at all times.

Question 4

Enhancers

Answer 4

Genes required for basic cellular function and expressed in nearly all cells at all times.

Question 5

Cis Motifs

Answer 5

Short DNA sequences in or near a gene that are binding sites for transcription factors; includes promoters, enhancers, silencers.

Question 6

Promoter

Answer 6

A DNA sequence upstream of a gene where RNA polymerase and general transcription factors bind to initiate transcription.

Question 7

General Transcription Factors

Answer 7

Proteins that are required for the transcription of all genes; they help position RNA polymerase and initiate transcription.

Question 8

Regulatory Transcription Factors

Answer 8

Proteins that bind to specific DNA sequences (like enhancers) to increase or decrease transcription of specific genes.

Question 9

RNA Polymerase

Answer 9

The enzyme that synthesizes RNA from a DNA template during transcription.

Question 10

Epigenetics

Answer 10

Heritable changes in gene expression that do not involve changes to the DNA sequence itself.

Question 11

Epigenome

Answer 11

The collection of epigenetic modifications across the entire genome, including DNA methylation and histone modification.

Question 12

Histone

Answer 12

Protein around which DNA is wrapped to form chromatin. Histone modifications affect gene expression.

Question 13

Chromatin

Answer 13

The complex of DNA and histone proteins in the nucleus. It can be tightly or loosely packed, affecting gene expression.

Question 14

Accessible/Active Chromatin

Answer 14

Loosely packed chromatin that allows transcription machinery to access genes (often euchromatin).

Question 15

Inaccessible/Repressed Chromatin

Answer 15

Tightly packed chromatin that prevents transcription (often heterochromatin).

Question 16

Heterochromatin

Answer 16

Densely packed chromatin that is typically gene-poor and transcriptionally inactive.

Question 17

Repetitive DNA

Answer 17

DNA sequences that are repeated many times in the genome, often found in heterochromatin.

Question 18

Euchromatin

Answer 18

Loosely packed chromatin that is rich in genes and generally transcriptionally active.

Question 19

DNA Methylation

Answer 19

Addition of a methyl group to cytosine bases (usually at CpG sites); associated with gene repression.

Question 20

Histone methylation: H3K27me3 and H3K9me3

Answer 20

Associated with gene silencing and repressed chromatin.

Question 21

Histone methylation: H3K4me3

Answer 21

Associated with gene activation and open chromatin.

Question 22

Histone Acetylation

Answer 22

Addition of acetyl groups to histones; loosens chromatin structure, generally associated with active transcription.

Question 23

Enhancer Accessibility

Answer 23

Whether or not an enhancer region is open (accessible) in a specific cell type.

Question 24

Presence of Regulatory Transcription Factors

Answer 24

Whether a particular cell type has the necessary transcription factors to activate specific genes.

Question 25

Activity of Regulatory Transcription Factors

Answer 25

Whether those transcription factors are in an active form (can be regulated by signals, phosphorylation, etc.).

Question 26

Alternative Splicing

Answer 26

A post-transcriptional process in which different combinations of exons are joined together to create multiple mRNA transcripts from the same gene.

Question 27

Nuclear Export

Answer 27

The transport of RNA (e.g., mRNA) from the nucleus to the cytoplasm for translation.

Question 28

siRNA (small interfering RNA)

Answer 28

Small RNA molecules that guide degradation of specific mRNAs, silencing gene expression.

Question 29

miRNA (microRNA)

Answer 29

Small RNA molecules that bind to mRNA and repress translation or trigger degradation.

Question 30

Protein Posttranslational Modification

Answer 30

Chemical modifications made to proteins after translation (e.g., phosphorylation, acetylation) that affect function, activity, or localization.

Question 31

Protein Folding, Stability, Subcellular localization

Answer 31

Processes affecting how proteins acquire their functional shape, how stable they are, and where they are directed inside the cell.