Biology Answers

 During which phase of meiosis does variation occur?

anaphase I

cytokinesis

interphase

telophase I

Male cats are either black (B) or orange (O). Females are black, orange, or calico, which has patches of black and orange. Calico is formed from the codominance between the two alleles in the heterozygote, so a calico cat is (X^B X^O).  Give the genotype and phenotype ratio of a cross between an orange male cat and a calico cat.

The trait that is masked by the dominant trait is the _____ trait.

recessive

cross

purebred

hybrid

What is the largest human organ?

R0 is: a) The death rate as a result of pathogen infection b) The percentage of a population that must be infected/vaccinated to achieve herd immunity c) The transmissibility of the pathogen, how many people an infected person is expected to infect d) The rate of morbidity (suffering/disease) as a result of pathogen infection e) The rate of full recovery from pathogen associated disease

What distinguishes what the Chinese first practiced for variolation from what Edward Jenner did? a) The Chinese used cowpox virus scabs, not smallpox virus scabs which Jenner used b) The Chinese used smallpox virus for variolation two times per person, Jenner smallpox only once per person c) Edward Jenner combined smallpox scabs with scabs from bacterial infections d) Edward Jenner used cowpox virus scabs, not smallpox virus scabs which the Chinese used e) There is no distinction, both the Chinese and Jenner used smallpox virus scabs twice per person for maximum effectiveness

Free fatty acids can move from adipose tissue to the liver or muscles in the bloodstream by: (select one) 

a. associated with serum albumin 

b. use special cofactors carriers 

c. independent water-soluble compounds 

d. use erythrocyte receptors 

e. use modifying enzymes 

The rate of the enzymatic reaction was measured at substrate concentrations lower than Km. In these cases, the dependence of the steady state rate on the substrate concentration is best described by: (select one or more) 

a. is equal to Km 

b. the speed is constant - Vmax 

c. does not depend on the substrate concentration 

d. proportional to the substrate concentration 

e. depends on the concentration of the enzyme and the substrate

Which of the following statements about the pentose phosphate pathway is NOT true? (select one) 

a. the electron acceptor is NADP + 

b. gives precursors for the synthesis of NK, ATP, NAD +, coenzyme A, FAD, FMN 

c. is very active in rapidly dividing cells - bone marrow, skin, intestinal mucosa 

d. a major route for the breakdown of glucose in animal tissues 

For the reaction: A + B = C + D, ∆Go ’= + 1kJ / mol. This reaction will proceed spontaneously in the right direction if: (select one) 

a. the concentration of A increases a hundredfold 

b. the concentration of both A and D decreases a hundredfold 

c. the concentration of B decreases a hundredfold 

d. the concentration of C increases a hundredfold 

e. the concentration of both A and D increases one hundredfold 

Which of the following statements about biological membranes are true? (select one or more) 

a. they are made up mainly of lipids and carbohydrates 

b. contain receptors for specific ligands (stimuli) 

c. they perform energy transformations in photosynthesis and oxidative phosphorylation 

d. are able to generate signals 

e. represent a boundary between the cell and the environment that exhibits selective permeability