Lab Exam 2 BIO212

Cystic fibrosis is due to an abnormal recessive gene (c). Only homozygous recessive individuals exhibit this disease. If the parents are both heterozygous for cystic fibrosis (Cc), what percentage of their children will have cystic fibrosis? _____________%

25%

If a woman and a man who both carry the trait for sickle cell anemia have children, what percentage of the various phenotypes would you expect from a cross between these individuals?

25% with sickle cell anemia 50% with sickle cell trait 25% with normal hemoglobin

In humans, syndactyly (webbed fingers) is inherited by possession of a dominant allele (S). If a man who is homozygous and has normal digits (ss) marries a woman who is heterozygous for syndactyly and has webbed digits, what proportion of their children would be expected to have webbed digits? ____ _____%

50%

Give an explanation for the different adult dental formulas in cats and humans

Cats are carnivores and need extra incisors for biting. They have a reduced need for grinding and thus have fewer molars.

Sex chromosomes

Chromosomes that determine genetic sex

Autosomes

Chromosomes that determine most body characteristics

Phenotype

Expression of a genetic trait

Alleles

Genes for the same trait that may have different expressions

Recessive

Genes not expressed unless they are present in homozygous condition

If a child's phenotype is blood type A and mother also has the phenotype A, list the potential genotypes for the father of the child.

IAIA, IAIB, IiIi, or IAIi

What differences did you observe between the origins of the left carotid arteries in the cat and the human?

In the cat, both the R. and L. common carotid arteries branch off the R. brachiocephalic artery. In humans, the L. common carotid branches directly off the aortic arch; only the R. common carotid branches off the brachiocephalic artery

Between the origins of the internal and external iliac arteries?

In the cat, the aorta gives off the two external iliac arteries, then persists briefly before dividing into the two internal iliac arteries and the median sacral artery; there are no common iliac arteries. In humans, the external and internal iliac arteries arise by branching off the common iliac arteries.

How do the relative sizes of the external and internal jugular veins differ in the cat and human?

In the cat, the external jugular vein is larger. In humans, the internal jugular vein is larger.

Tail length on a bobcat is controlled by incomplete dominance. The alleles are T for normal tail length and t for tail-lessness. How would you describe the tails of heterozygous (Tt) bobcats?

Intermediate length

Does the cat have a uvula?

No

Does the cat have an appendix?

No

The days before DNA fingerprinting, blood typing was used as a means of paternity testing. It was not possible to prove paternity, since many males would have the same blood type, but it was possible to exclude a man who couldn't possibly be the father based on blood typing. For a child with type O blood born to a mother with type A blood, is a man blood type AB possibly the father? Why or why not?

No, a man with blood type AB could not be the father because his genotype is IAIB. In order for the child to have type O blood, they must have the genotype IiIi. If the mother has type A blood, then her genotype could be IAIi or IAIA, and she would have had the child with a male that has either IiIi (only possibility if she is IAIA), IBIi or IAIi.

Heterozygous

Situation in which an individual has different alleles making up his or her genotype for a particular trait

Homozygous

Situation in which an individual has identical alleles for a particular trait

Describe the appearance of lung tissue under the dissection microscope?

Spongy-looking with small, irregular openings

Describe the location of the following blood vessels: aortic arch

The aorta as it arches to the left

Describe the location of the following blood vessels: ascending aorta

The aorta as it emerges from the heart and travels toward the head

Describe the location of the following blood vessels: Descending abdominal aorta

The aorta as it passes through the abdominal cavity

Describe the location of the following blood vessels: Descending thoracic aorta

The aorta as it passes through the thoracic cavity

Describe the appearance of the bronchial tree in the cat lung?

The bronchial tree is a series of branching tubing. The main (primary) bronchi are large; subsequent branches are smaller and smaller in diameter.

Compare the appearance of tongue papillae in cats and humans.

The cat has numerous sharp, bristly filiform papillae. Human filiform papillae are less numerous, blunted, and softer.

Compare the number of lobes of the liver in cats and humans.

The cat liver has five lobes; the human liver has four.

Genotype

The combination of alleles for a given gene

Dominant

The more potent gene allele; masks the expression of the less potent allele

How do the villi differ in the duodenum and the ileum? Explain.

The villi in the duodenum are more elongated and more numerous than those in the ileum. Villi contribute to the increase in surface area that is necessary for absorption of nutrients, especially in the duodenum. Most absorption occurs in the proximal portion of the small intestine.

Are the cartilaginous rings in the cat trachea complete or incomplete?

They are shaped like Cs and incomplete.

What does it mean when someone says a particular characteristic is sex-linked?

This means that is is carried on the female X chromosome

You are a male, and you have been told that hemophilia "runs in your genes." Whose ancestors, your mother's or your father's, should you investigate? Why?

Your mother's because your mother is the one who can give you the X chromosome.

In the cat the inferior vena cava is also called ____, and the superior vena cava is also referred to as _____

postcava; precava