Chapter 3: The Human Genome: Gene Structure and Function

Question 1

the amplification of genetic information goes from what to where?

Answer 1

from genome to proteome to gene networks, and ultimately to cellular function

Question 2

What are introns?

Answer 2

pre-mRNA that is transcribed in the nucleus not present in mature RNA

Question 3

What are exons?

Answer 3

segments of genes that actually encode for the amino acid sequence of the protein

Question 4

What are the structural features of a human gene?

Answer 4

5' promotor
enhancer
silcener
repressor
3' UTR containing AATAAA signal for polyadenylation

Question 5

What are gene families?

Answer 5

they share closely related DNA and amino sqequences

Question 6

What is an example of a gene family?

Answer 6

Beta-globin cluster on chromosome 11 and alpha-globin cluster on chromosome 16

Question 7

What are psuedogenes?

Answer 7

DNA sequences that resemble known genes but are nonfunctional. They lack introns

Question 8

What are the two types of psuedogenes?

Answer 8

1) non-processed-nonfunctional “dead” genes

2) processed- arise from retrotansposition

Question 9

How does retrotransposition occur?

Answer 9

reverse transcription of a DNA copy of mRNA and later integration of the DNA copy back into the genome

Question 10

What is an important class of noncoding RNA genes?

Answer 10

miRNA genes

Question 11

What do miRNA genes do?

Answer 11

they control expression and repression of other genes during development

Question 12

How does initiation of transcription occur?

Answer 12

by influence of the promoter

Question 13

Where is the start site of RNA?

Answer 13

on the 5’ UTR

Question 14

What is RNA splicing?

Answer 14

removal of introns and splicing together exons

Question 15

Which nucleotides are introns rich in?

Answer 15

GT

Question 16

Which nucleotides are exons rich in?

Answer 16

AG

Question 17

What directionality does protein translation have?

Answer 17

amino to carboxyl terminus

Question 18

How is the beta-globin gene transcribed?

Answer 18

from telomere to centromere

Question 19

The TATA box is rich in which nucleotides?

Answer 19

A’s and T’s

Question 20

What does the TATA box do?

Answer 20

determines the start of transcription

Question 21

What does the CAT box do?

Answer 21

it is the second conserved region upstream of TATA

Question 22

What happens if there is a mutation in either the TATA or the CAT box?

Answer 22

It would cause a reduction in transcription

Question 23

What are the two components of the promoter?

Answer 23

TATA box and CAT box

Question 24

What are housekeeping genes?

Answer 24

repeated regions of CPG island; they lack TATA or CAT boxes

Question 25

What inhibits or silences the function of housekeeping genes?

Answer 25

hypermethylation of the CPG islands

Question 26

The promoters of housekeeping genes are rich in what nucleotides?

Answer 26

CG

Question 27

What is an example where silencing of a housekeeping gene is necessary?

Answer 27

hypermetylation of a second X chromosome in women

Question 28

What is meant by degenerate?

Answer 28

some amino acids are coded by multiple codons

Question 29

What are enhancers?

Answer 29

They are an activating sequence that act at a distance to stimulate transcription

Question 30

What is the Locus Control Region?

Answer 30

establishes proper upper chromatin context for high-level expression, located upstream

Question 31

How is RNA splicing guided?

Answer 31

specific sequences in the primary RNA transcript

Question 32

What establishes the reading frame of the mRNA

Answer 32

AUG

Question 33

What is somatic rearrangement

Answer 33

the cutting and pasting of DNA sequences in lymphocyte precursor cells to rearrange genes to generate antibody diversity

Question 34

What is allelic exclusion?

Answer 34

only 1 or 2 of parental alleles of autosomal loci are expressed