BIOL1003 Lecture Notes - Lecture 2: Tyrosinase, Cellular Compartment, Auxotrophy

2. Explain the structural role of the four different categories of biomolecules within a cell.

3. Explain how water, a steroid hormone, and a monosaccharide are transported into a cell down their concentration gradient and explain why the different molecules are transported in different ways.

4. Explain which forms of transport require energy and why, and how ATP facilitates energy-dependent transport.

5. All of the different types of biomolecules can serve as energy sources. Explain which biomolecules are catabolized in which metabolic pathways.

6. Whether or not the cellular machinery is in place for particular catabolic reactions to go forward depends on which genes are being expressed. Explain the different points, in a eukaryotic cell, at which gene expression might be regulated, and how.

7. The primary tasks of any organism are survival and reproduction. Acquiring biomolecules and catabolizing them to generate energy is a major factor in survival. For reproduction to occur, DNA must first be replicated so that it can be passed on. Describe the process of DNA replication.

8. If you wanted to replicate DNA artificially in large quantities, how would you go about it?

9. Once DNA has been replicated, what is the sequence of events in the cell cycle and in cell division that produce the gametes for sexual reproduction? Where does this event fit, along with other cell cycles, in the life cycle of the organism?

10. A number of physical traits in humans are controlled by a simple dominant/recessive relationship between two alleles; here are some examples (dominant/recessive):

Widow’s peak/no widow’s peak

Free earlobes/attached earlobes

Cleft chin/no cleft chin

Dimples/no dimples

Freckles/no freckles

Naturally curly hair (really curly, not wavy)/straight hair

Make a pedigree of your immediate family indicating the possible genotype of each family member (for the six genes listed above) based on their phenotype. If you are adopted, indicate the possible genotypes and phenotypes of your parents. You may make this part up.

13. The arms of a human and the wing of a bat are _________________ structures, composed of the same bones that have been modified for different functions.

14. Xeroderma pigmentosum is an autosomal recessive genetic disorder. People who are homozygous for the disease-causing allele have skin that is damaged by exposure to ultraviolet radiation; this can lead to skin cancer at an early age. The mutation that causes this disorder is in a gene that functions:

15. The Amish are a religious sect descended from a small group of colonists who came to the United States over 200 years ago. Their religious beliefs have kept them isolated from society. The Amish have a much higher than average incidence of both polydactyly (extra fingers and toes) and dwarfism in their communities. This is most likely explained by:

16. In the structure of DNA that Watson and Crick proposed, the sides of the "ladder" of the DNA molecule are always the same distance apart, making the molecule a constant width. This occurs because when the bases hydrogen bond to form the rungs of the "ladder", a:

17. The RNA transcript of DNA that travels to the cytoplasm, carrying the instructions to make a protein, is called:

18. When DNA is replicated, the error rate is approximately one error for every 10,000 nucleotides copied. However, that error rate is reduced to only 1 error for every 1 billion nucleotides. The DNA sequence is "corrected" by:

19. Mendel's principle of segregation says that:

20. Tay-Sachs disease is lethal before reproductive age, but the allele persists in Louisiana French Canadians because:

21. Physical features that are similar in organisms which are not closely related to each other are most likely a result of ____________. A good example of this is the similarities seen between some marsupial and placental mammals.

22. In humans, which of the following sex chromosome compliments could be found in males?

23. The proteins that are associated with eukaryotic chromosomes:

24. A sequence of DNA nucleotides that contains the information to produce a single protein is a(n):

___1. Nationally, the most common cause of Down Syndrome is
a. nondisjunction of Chromosome 21 during meiosis
b. translocation of Chromosome 21 onto another chromosome
c. inversion of a large section of Chromosome 21
d. deletion of the Down Syndrome gene
___2. In humans, sex is determined by
a. The presence or absence of the Y chromosome
b. The ratio of X chromosomes to sets of autosomes
c. The temperature during fetal development
d. Which parent is stronger at the time of conception
___3. A translocation is
a. a chromosomal abnormality in which a piece of one chromosome breaks off and attaches to a different chromosome
b. an abnormality in which the chromosomes are translocated out of the nucleus
c. a condition in which the chromosome has broken in two places and come back together with the middle segment backward
d. an abnormality in which there is an extra copy of one chromosome
___ 4. In snapdragons, a red-flowered plant crossed with a white-flowered plant produces all pink-flowered offspring. But crossing two pink-flowered plants produces red, pink, and white in a 1:2:1 ratio. This is a good example of
a. Incomplete dominance
b. Dominance of the red allele over the white allele
c. Lethal effects of the pink allele
d. Sex-linkage of the flower-color alleles
___ 5. If a person with type AB blood marries a person with Type O blood, what blood types are possible in their children? (Assume this trait is a single-gene trait, not complicated by interaction with other genes).
a. A, B, AB, or O
b. A or B only
c. AB or O only
d. AB only 2
___6. In what phase of meiosis are haploid nuclei first formed? a. Anaphase I b. Metaphase II c. Telophase II d. Metaphase I e. Telophase I
___7. What is the phenotype of a heterozygous tall pea plant? a. tall b. Tt c. TT d. tt e. dominant
___ 8. If genes A and B are far apart on a chromosome, and A and C are close together, which of the following observations is expected?
a. Crossing over will occur more often between A and C than between A and B
b. Crossing over will occur at equal frequencies between A and C, and between A and B
c. Crossing over will occur more often between A and B than between A and C
___9. Sometimes an organism’s genotype for one gene masks the effect of a different gene. This phenomenon is called
a. Dominance
b. Incomplete dominance
c. Co-dominance
d. Epistasis
e. Variable expressivity
___10. The dominant allele of a gene is
a. The one that is expressed most often in a population
b. The one that is expressed most often in any particular cross
c. The one that is expressed in an individual that has two different alleles
d. The one that is most healthy to have, that gives the greatest fitness
___11. In human cells, DNA replication occurs
a. In S phase of interphase
b. In G1 phase of interphase
c. In G2 phase of interphase
d. In prophase of mitosis
e. Whenever the cell needs to read the DNA to make proteins
___ 12. A process in which recipient cells take up genes from DNA molecules floating free in the surrounding medium is called
a. conjugation
b. specialized transduction
c. generalized transduction
d. transformation 3
___ 13. Most calico cats are female. However, a few rare males are observed. What is the genotype of a male calico cat?
a. X BX 0
b. X OY
c. X BY
d. X BYY
e. X BX OY
___ 14. A type of red-green color-blindness is a sex-linked (X-linked) recessive trait in humans. Can a woman have this type of color-blindness?
a. Yes, a woman could be color-blind if her mother and father were both heterozygous.
b. Yes, a woman could be color-blind but only if she has an abnormal number of sex chromosomes.
c. No, women can't show sex-linked traits because they lack a Y chromosome.
d. No, women can't show sex-linked traits because they have two X chromosomes.
e. Yes, a woman could be color-blind if her father was color-blind and her mother was a carrier (heterozygous).