Test 2, Deck 3

Question 1

Red-green color blindness is caused by an X linked recessive allele in humans. Normal woman with colorblind father mates with color blind man. What is the probability that they will produce a colorblind son?

Answer 1

1/4

Question 2

Red-green color blindness is caused by an X linked recessive allele in humans. Normal woman with colorblind father mates with color blind man. What genotypes are possible for the father of the normal women?

Answer 2

X(allele a) Y

Question 3

Researchers working with gene sequences report the coding strand. What is the coding sequence of this string of DNA nucleotide: 3’ GATTACA 5’

Answer 3

Coding strand: 5’ CTAATGA 3’

Question 4

What would be the RNA sequence transcribed from the DNA: 5’ GATTACCA 3’

Answer 4

3’ CUAAUGGU 5’ or

5’ UGGUAAUC 3’

Question 5

Indicate the direction of transcription: 5’ GATTACCA 3’

Answer 5

left

Question 6

Indicate the direction of transcription: 3’ GATTACA 5’

Answer 6

right

Question 7

What would be the RNA sequence from DNA sequence: 3’ GATTACA 5’

Answer 7

5’ CUAAUGU 3’

Question 8

X-linked dominant…

X-linked recessive…

Answer 8

Affected father affect their daughters

Affected mothers affect their sons

Question 9

Calico cats are always female, how could you get a calico male ?

Answer 9

XXY - since male are usually XY (one X from mother one Y from father), meiosis has to be messed up to produce this offspring. For example, two X chromosomes get stuck in one part of the cell and produces a cell with two X chromosomes and the mates with a normal Y gamete.

Question 10

What explains calico females?

Answer 10

Calico cats are female because they have to have both X-linked allele orange and black. X(orange)X(black). Since in female there is X-chromosome inactivation, in each cell randomly the cell inactives one of these two alleles and expresses the other… different patches of color

Question 11

T or F: Ribose and phosphate make up the backbone “sides” of a DNA molecule.

Answer 11

F : deoxyribose and phosphate

Question 12

T or F: Hydrogen bond forms 3’ to 5’ linkage

Answer 12

F: carbon bond

Question 13

T or F: Phosphodiester bonds link nitrogenous bases and hydrogen bonds link nucleotides

Answer 13

F: contrary

Question 14

T or F: hydrogen bonds link nitrogenous bases and Phosphodiester bonds link nucleotides

Answer 14

T : phosphodiester bonds the phosphate groups and carbons and sugar together

Question 15

Match the DNA nucleotides 
A
C
G
U

Answer 15

T
G
C
A

Question 16

Identify the molecule : A,G,C,U with two OH groups on sugar

Answer 16

RNA because of uracil and of the two OH groups meaning ribose sugar

Question 17

Identify the molecule: Adenine, 2 OH groups

Answer 17

RNA 2 OH groups = ribose

Question 18

An insertion occurs within a gene which results in the addition of sequences that are recognized as the beginning and end of an intron.

a. How would this affect transcription?
b. How would this affect RNA processing?
c. How would this affect translation?
d. How would this affect the protein?

Answer 18

a The transcription would occur normally
b Introns would be removed as usual except that a new intron (from insertion) would be recognized.
c Translation would be normal except that the mRNA being translated would be shorter
d The protein would be missing amino acids - it may not be functional or function might be altered

Question 19

Why are introns removed?

Answer 19

Introns are removed in order to produce the correct amino acid sequence since they do not participate in the protein synthesis. Not removing the introns would add extra amino acids.

Question 20

How are tRNA molecules produced?

Answer 20

They are transcribed from the genes in the nucleus using a special RNA polymerase (pol lll).