Researchers have determined that domestic cats have around 20,000 genes but produce over 32,000 proteins. What is the best explanation for how there can be more proteins than genes?

What is necessary in order for a cell to move ions against their concentration gradient and establish a high concentration of ions on one side of a membrane?

What must be present in the DNA just upstream from a gene in order for the gene to be expressed (transcribed and translated)?

When two atoms form a chemical bond, one takes an electron from the other. The two atoms then have full, opposite charges and and attracted to each other. This is an example of what type of bond?

Suppose that a reaction in which a chemical bond is broken has ΔG of – 5.2 kcal/mol. Forming another bond has ΔG of + 3.3 kcal/mol. Could these two reactions be coupled so the energy released by one reaction is used to drive the other?

There are both similarities and differences in cellular respiration and photosynthesis. Summarize some of them by choosing the correct answers from the drop-down boxes. The initial energy input that starts glycolysis and is used to drive cellular respiration is [a]. The initial energy input used to drive photosynthesis is [b]. Both cellular respiration and photosynthesis involve electron transport chains (e.t.c.) in a membrane. The e.t.c. involved in cellular respiration is found in the [c]; the e.t.c involved in photosynthesis is found in the [d]. The immediate source of energy for the e.t.c. in cellular respiration is [e]; in photosynthesis, it is [f]. In cellular respiration, the e.t.c. is used to directly generate [g]; in photosynthesis, the e.t.c from PS II is used to directly generate [h], and the e.t.c from PS I is used to directly generate [i].

Yeast cells can generate ATP in the absence of oxygen. What is the primary way they maintain ATP production in the absence of oxygen?

Which of the following events occurs earliest in mitosis?

In a population, the frequency of allele B is 0.4 and the frequency of allele b is 0.6. What percentage of individuals in the population will have the genotype BB if the population is in Hardy-Weinberg equilibrium?

A point mutation changes a codon from 5′ UGG 3′ to 5′ UGU 3′. This changes the amino acid from tryptophan (which is nonpolar) to cysteine (which is polar). What is the most likely impact of this mutation on the protein’s structure and function?