Bio Final E2

Hemophilia is an X-linked, recessive trait such that an "N" gene produces a protein for normal blood clotting and an "n" gene codes for hemophilia. John and Mary come to you for your genetic counseling. Mary has hemophilia and David is normal. What can you tell them about the genetic probabilities of their offspring? A) all of their sons will have hemophilia. B) half of their daughters could have hemophilia. C) half of their daughters will be carriers for hemophilia and half will be homozygous normal. D) none of their children can have hemophilia.

A

Huntington's Disease is caused by a dominant, autosomal gene such that H= Huntington's Disease and h= normal. Which of the following is true if one of the parents has Huntington's Disease (Hh) and the other parent is normal (hh)? A) there's a 50:50 chance of passing on the disorder. B) all of the sons would have the disease and half of the daughters would be carriers. C) the odds are that 75% of their offspring could have the disorder. D) statistically, 25% of the offspring could have the disorder.

A

Let us suppose that in hallucinogenic mushrooms blue mushrooms (B) are dominant to yellow mushrooms (b). You have two populations of blue mushrooms. You suspect that one population is genotypically heterozygous (Bb) while the other is genotypically homozygous (BB). If that's true and you cross the two populations, what should you expect to see in the next batch of mushrooms? A) 100% blue mushrooms B) 50% blue and 50% yellow mushrooms C) 3 blue mushrooms for every 1 yellow mushroom D) the police

A

In a population of tropical birds, blue feathers (B) is dominant to white feathers (b) and long wings (W) is dominant to short wings (w). If a white-feathered, long-winged male bird (bbWw) mated with a blue-feathered, long-winged female bird (BbWw), what might their offspring look like? A) long-winged birds will outnumber short-winged ones. B) an offspring that is white-feathered and short-winged would not be impossible. C) there will be more blue-feathered birds than white-feathered. D) half of them would be blue-feathered with long wings.

A, B

Color-blindness is an X-linked, recessive trait such that "N" gene produces a protein for normal vision and an "n" gene codes for color-blindness. If Jack is color-blind, what must be true of his parents? A) his mother must be color-blind. B) his mother could be a carrier. C) his father must be color-blind. D) both parents must have normal vision.

B

Which kind of mutation would have the smallest chance of producing an incorrect protein? A) the deletion of one base from a DNA triplet. B) the substitution of one base in a DNA triplet. C) the inversion of a small section of DNA. D) all of the above would be equally disruptive.

B

Which of the following is not a part of the CRISPR-Cas9 technique? A) a messenger-RNA molecule is created to target a specific DNA sequence. B) a virus is used as a way to deliver a correct DNA base sequence. C) the Cas9 enzyme cuts out the target DNA. D) the m-RNA guides the Cas9 enzyme to the DNA site to be repaired.

B

A small percentage of females are XO. How could this abnormality occur? A) an egg containing an X and Y chromosome is fertilized by a sperm carrying a Y chromosome. B) the X and Y chromosomes do not separate during meiosis in sperm production and they end up in the same sperm cell, which then fertilizes an X-carrying egg. C) the X and Y chromosomes do not separate during sperm production and a sperm carrying no sex chromosomes fertilizes an X-carrying egg. D) during meiosis in sperm production, the original strand and the copy of the Y chromosome do not separate and end up in the same sperm cell that then fertilizes an X-carrying egg.

C

Let's suppose that skin color in elephants is a case of incomplete dominance such that RR= red elephants, WW= white elephants, and RW= pink elephants. You're a wildlife researcher and observe a pink elephant mating with another pink elephant. Your research partner asks you how many of the offspring might be pink as well. What do you tell her? A) none since all of the offspring are either red or white. B) there's a 3:1 chance that the baby will be pink. C) there's a 50:50 chance that the baby could be pink. D) only 25% of them could possibly be pink.

C

Let's suppose that the feather color of some tropical bird is a result of epistasis in which two pairs of genes (the P and B genes) interact to produce the phenotype. P= darker pigmentation in general, p= lighter pigmentation in general, B= presence of blue pigment, and b= presence of green pigment. If you had a bird whose genotype was (ppbb), what is its most likely feather color? A) dark green B) light blue C) light green D) dark blue

C

If coat color in horses was due to co-dominance such that horses can have white coats (WW), black coats (baby), or coats with black and white stripes like a zebra (WB). You work on a Kentucky horse farm and breed black horses with horses that have black and white stripes. A buyer wants to buy horses that look like zebras and wants to know what percentage of the offspring from the mating will look like that. What do you tell him? A) all of the horses will look like zebras. B) there should be 3 black horses for every 1 striped horse. C) 25% should have black and white stripes. D) 50% of the offspring will probably look like zebras.

D

PKU is caused by a recessive, autosomal mutation such that N= normal and n= PKU. John is a carrier for PKU and Mary has PKU. What can you tell them regarding children that they might have someday? A) there is insufficient evidence to propose a probability statement concerning offspring. B) you have a one in four chance of having a PKU baby. C) half of your children could be homozygous normal and not even carry PKU. D) half of your children can have the disease and half could be carriers.

D

Which of the following best illustrates the production of a transgenic organism? A) a sheep that is a genetic copy of another sheep that donated the DNA. B) cattle that are bred through multiple crossings to provide more meat. C) a child born to a woman who has a totally different genetic make-up than the baby. D) a plant with an inserted gene from another species that protects against pests.

D