Question

1. the proteins that form the hair shaft are made only in certain cells. this shows that: a. all genes are expressed equally b. hair proteins are made randomly c. gene expression differs between cell types d. dna is missing in other cells 2. if regulatory proteins fail to control cell division in hair follicles, what might happen? a. the ribosomes stop functioning b. uncontrolled cell growth could lead to tumors c. hair color changes overnight d. dna disappears from the nucleus 3. why do only scalp hair cells produce uhs traits while skin cells remain normal? a. scalp cells express the mutated hair - shaft gene b. the mutation destroys dna in skin cells c. hair cells have more chromosomes d. the mutation is caused by brushing only scalp hair ls.bio.6.1 use models to explain how dna is passed from parents to offspring through the processes of meiosis and fertilization in sexual reproduction. 1. how does the uhs gene pass from parents to offspring? a. through proteins in hair follicles b. through dna in gametes formed during meiosis c. mitosis of somatic cells d. through mutations only in skin cells 2. place the steps of sexual reproduction in order. a. offspring receive genes from both parents b. meiosis produces gametes c. fertilization combines gametes

Explanation:

1. Question 1:

• Option a: All genes are not expressed equally. Different cells express different genes.
• Option b: Hair proteins are not made randomly. They are made based on gene expression in specific cells.
• Option c: Gene expression differs between cell types. Hair - shaft proteins are made only in certain cells because only those cells express the relevant genes.
• Option d: DNA is not missing in other cells. All somatic cells have the same DNA (in most cases).

1. Question 2:

• Option a: Ribosomes do not stop functioning if regulatory proteins fail to control cell division. Ribosome function is related to protein synthesis.
• Option b: Uncontrolled cell growth (due to failure of regulatory proteins in cell - division control) can lead to tumors.
• Option c: Hair color change overnight is not related to failure of regulatory proteins in cell division.
• Option d: DNA does not disappear from the nucleus due to this failure.

1. Question 3:

• Option a: Scalp cells express the mutated hair - shaft gene, which is why they produce UHS traits while skin cells (that do not express this gene) remain normal.
• Option b: The mutation does not destroy DNA in skin cells. Skin cells just do not express the UHS - related gene.
• Option c: Hair cells do not have more chromosomes. Most somatic cells have the same number of chromosomes.
• Option d: Brushing scalp hair does not cause the mutation. Mutations can be due to various factors like radiation, chemicals, etc., but not brushing.

1. Question 4 (LS.Bio.6.1 - 1):

• Option a: Proteins in hair follicles do not pass the UHS gene. DNA passes genes.
• Option b: DNA in gametes (formed during meiosis) passes genes from parents to offspring.
• Option c: Mitosis of somatic cells is for growth and repair, not for passing genes to offspring.
• Option d: Mutations in skin cells (if any) are not the way the UHS gene is passed. Gametes (with DNA) pass genes.

1. Question 5 (LS.Bio.6.1 - 2):

• First, meiosis produces gametes (B). Then, fertilization combines gametes (C). Finally, offspring receive genes from both parents (A).

Answer:

1. C. Gene expression differs between cell types
2. B. Uncontrolled cell growth could lead to tumors
3. A. Scalp cells express the mutated hair - shaft gene
4. B. Through DNA in gametes formed during meiosis
5. B, C, A