Biochemistry
Which of the following best explains why the molecules are classified as lipids?
A. They contain phosphorus.
B. They form a double layer.
C. They are made up of fatty acids.
D. They are found in the cell membrane.
An unfertilized egg cell has six chromosomes. After fertilization, how many chromosomes should the zygote have?
A. 3
B. 6
C. 12
D. 24
Bacteria that live in the digestive systems of cows help break down the plants that cows eat, providing nutrients to cows. The digestive systems of cows offer a safe environment in which the bacteria can live and reproduce.
Which type of relationship exists between the bacteria and the cows?
A. commensalism
B. mutualism
C. parasitism
D. predation
In pea plants, the allele for smooth seeds (R) is dominant to the allele for wrinkled seeds (r). Two parent plants are crossed. Almost half of the offspring have smooth seeds, while the rest of the offspring have wrinkled seeds.
Which of the following identifies the most likely genotypes of the two parent plants?
A. RR and Rr
B. RR and rr
C. Rr and rr
D. Rr and Rr
Placental mammals are one group of mammals. Using DNA evidence, scientists have concluded that the ancestor of placental mammals diverged from other mammal groups about 160 million years ago.
The analysis of which of the following types of evidence would best verify this conclusion?
A. behaviors
B. cells
C. diets
D. fossils
Some bacteria produce cellulase, a substance that speeds up the breakdown of cellulose in plant cell walls. Cellulase is an example of which of the following?
A. a carbohydrate
B. an enzyme
C. a hormone
D. an organelle
A student places four small aquatic snails in a test tube containing bromothymol blue solution. The solution will change color from blue to yellow if the carbon dioxide level increases. The student seals the test tube and notes that the solution is blue. After a few hours, the student observes that the solution is yellow.
What cellular process did the snails perform that caused the color of the solution to change?
A. cellular respiration
B. chemical digestion
C. fermentation
D. photosynthesis
Carbon fixation is an important part of the carbon cycle. Carbon fixation is the conversion of carbon dioxide into organic compounds such as glucose.Which of the following organisms cannot fix carbon?
A. grass
B. green algae
C. mushrooms
D. oak trees
In fruit flies, the gene for eye color is on the X chromosome. The allele for red eyes is dominant to the allele for white eyes. A researcher crosses a heterozygous red-eyed female fly (XRXr) with a red-eyed male fly (XRY).
Which of the following statements describes the expected outcome of the cross?
A. All the female and male offspring will have red eyes.
B. All the female and male offspring will have white eyes.
C. All the female offspring and half the male offspring will have red eyes.
D. Half the female offspring and all the male offspring will have white eyes.
Snakes such as boa constrictors and pythons have tiny leg bones buried in their muscles. These leg bones are vestigial structures that have little or no known function in snakes.
Which best explains the presence of these vestigial structures in snakes?
A. Snakes evolved from organisms with legs.
B. Snakes are developing legs for walking on land.
C. Snakes born with an extra set of DNA develop legs as they mature.
D. Snakes have only one copy of the allele for legs in their chromosome
Which of the following best describes how enzymes affect chemical reactions?
A. They speed up the rate of reactions.
B. They change the reactants into ions.
C. They dissolve the products of reactions.
D. They take the place of one of the reactants.
A researcher is studying a sample of cells taken from an organism found in the Arctic Ocean. The researcher makes the following observations about the cells:
Based on these observations, the organism should be classified as which of the following?
A. a plant
B. a fungus
C. an animal
D. a bacterium
Which of the following processes removes carbon from the air and uses it to make organic compounds?
A. combustion
B. decomposition
C. photosynthesis
D. respiration
Which of the following is a reason for DNA replication in skin cells?
A. to produce identical daughter skin cells
B. to enable the skin cells to make more proteins
C. to allow the skin cells to adapt to a changing environment
D. to ensure daughter skin cells will have higher genetic diversity
For many years, biologists disagreed about whether giant pandas are more closely related to raccoons or bears. Which of the following types of evidence was most useful in determining the evolutionary relationship of giant pandas to other animals?
A. diet
B. behavior
C. genetic sequences
D. anatomical features
Cholesterol belongs to which category of organic molecules?
A. carbohydrates
B. lipids
C. nucleic acids
D. proteins
Several parts of an animal cell are involved in the processes of protein synthesis, packaging, and export. Which of the following correctly places the cell parts in the order in which they are involved?
.
A. nucleus → vacuole → cell membrane
B. mitochondria → vacuole → cell membrane
C. ribosome → endoplasmic reticulum → Golgi complex → cell membrane
D. lysosome → endoplasmic reticulum → Golgi complex → cell membrane
Which of the following expressions can be used to calculate the change in the size of a population?
A. (births – deaths) + (immigrants – emigrants)
B. (births + deaths) + (immigrants – emigrants)
C. (births – deaths) + (immigrants + emigrants)
D. (births + deaths) + (immigrants + emigrants)
Which of the following describes how DNA determines genetic inheritance?
A. A single nucleotide codes for a genetic trait.
B. A pair of complementary nucleotides codes for a genetic trait.
C. A set of three nucleotides in a specific order codes for a genetic trait.
D. A long sequence of nucleotides in a specific order codes for a genetic trait.
Scientists compared levels of a particular chemical found in the blood of two groups of male birds. The average concentration of the chemical was significantly higher in one group of males than in the other group of males. It was determined that the chemical caused different mating behaviors depending upon its concentration in the blood.Based on the information, this chemical is most likely which type of compound?
A. an antibody
B. a hormone
C. a nucleic acid
D. a sugar
Which of the following elements is expected to be most abundant in organic fertilizers made from animal products?
A. copper
B. nickel
C. phosphorus
D. zinc
The products of photosynthesis are carbohydrates and oxygen. Which process uses these substances as reactants?
A. cellular respiration
B. fertilization
C. mechanical digestion
D. translation
Which of the following statements describes a role of plants in the water cycle?
A. Plants release water from their roots into the soil.
B. Plants transfer water to bacteria during nitrogen fixation.
C. Plants release water vapor into the atmosphere during transpiration.
D. Plants convert water vapor into carbon dioxide during photosynthesis.
Six puppies from a single litter have the following genotypes for a certain trait: AA, Aa, AA, aa, aa, Aa. Which of the following describes how these alleles were passed on from parent to offspring?
A. Each parent dog randomly passed on a dominant allele (A) or a recessive allele (a) to each offspring.
B. The male dog passed on a dominant allele (A) to each female offspring and a recessive allele (a) to each male offspring.
C. The female dog chose to pass on either homozygous dominant alleles (AA) or homozygous recessive alleles (aa) to each offspring.
D. One parent dog passed on a dominant allele (A) to each offspring, and the other parent dog passed on a recessive allele (a) to each offspring.
What is the typical path that dietary cholesterol takes through the digestive system, from the mouth to where it is absorbed into the bloodstream?
A. mouth → esophagus → pharynx → small intestine → stomach
B. mouth → pharynx → esophagus → small intestine → stomach
C. mouth → pharynx → esophagus → stomach → small intestine
D. mouth → esophagus → stomach → pharynx → small intestine