Lecture 3- Genes

Question 1

gene

Answer 1

a segment of a DNA molecule

Question 2

intergenic DNA

Answer 2

DNA located between genes that are non-coding

Question 3

base pair

Answer 3

the unit length of a DNA molecule

Question 4

how long are the shortest genes

Answer 4

100 bp e.g tRNAs

Question 5

what is the length of the longest genes

Answer 5

about 2,400,000 bp e.g human muscle protein dystrophin

Question 6

what are genes split into

Answer 6

introns ( information not needed to make a protein)
exons ( contain information to make a protein)

Question 7

what is the average number of introns and exons in human genes

Answer 7

8 introns and 9 exons

Question 8

what is the mean intron length

Answer 8

3365 base pairs

Question 9

what is the mean exon length

Answer 9

145 base pairs

Question 10

what are the functional end products of gene expression

Answer 10

proteins and RNAs

Question 11

are all RNAs translated into proteins

Answer 11

no, they play important roles in the cell

Question 12

examples of non coding RNAs

Answer 12

rRNAs, tRNAs, snoRNAs, scRNAs, miRNA, siRNAs

Question 13

what percentage of the total RNAs are made up by coding RNAs

Answer 13

4% total

Question 14

what percentage of the total RNAs in the body are made up by non coding RNAs

Answer 14

96%

Question 15

simple multi gene family

Answer 15

all genes are the same

Question 16

when do single gene families occur

Answer 16

where the gene product is needed in large amounts e.g ribosomal RNA genes

Question 17

complex multigene family

Answer 17

genes are not identical but have similar DNA sequences

Question 18

what do complex multi gene families code for

Answer 18

similar but non-identical proteins
-proteins with slightly different functions which allow increased organismal complexity

Question 19

examples of multigene complex families

Answer 19

globin genes (bind and transport oxygen)

Question 20

how many multigene families do the globin genes form

Answer 20

two complex multigene families: alpha globin genes and beta globin genes

Question 21

where are the alpha-globin genes found

Answer 21

on chromosome 16

Question 22

What is the primary function of globin proteins?
A) Replicate DNA
B) Synthesize RNA
C) Bind and transport oxygen
D) Protect the cell membrane

Question 23

How do multigene families typically arise?
A) By random mutation
B) Through gene duplication
C) Through environmental adaptation
D) By recombination events

Question 24

The concept of a “molecular clock” helps measure:
A) Protein synthesis rate
B) Gene duplication speed
C) Rate of gene sequence changes
D) Time needed for gene expression

Question 25

Pseudogenes are:
A) Functional duplicates of other genes
B) Non-functional genes with altered sequences
C) Genes that code for ribosomal RNA
D) Genes that only occur in bacteria

Question 26

How many pseudogenes are present in the alpha-globin and beta-globin gene families?
A) 1 in alpha-globin, 1 in beta-globin
B) 4 in alpha-globin, 1 in beta-globin
C) 3 in each family
D) 2 in each family

Question 27

What does “kb” stand for in the context of DNA length?
A) Kilobit
B) Kilobyte
C) Kilobase pair
D) Karyotype base

Question 28

How is gene length commonly measured in genetics?
A) Number of amino acids
B) Kilobits
C) Base pairs (bp)
D) Percent of genome

Question 29

Which of the following best describes an exon?
A) A non-coding sequence within a gene
B) A sequence that codes for a part of the protein
C) A regulatory sequence upstream of the gene
D) A sequence that inhibits gene expression