MCAS Practice Cells and Chemistry #3

An unfertilized egg cell has six chromosomes. After fertilization, how many chromosomes should the zygote have?

• 3

• 6

• 12

• 24

The diagram below shows the structure of a bacterial cell.

Which of the following distinguishes this bacterial cell from eukaryotes?

• The bacterial cell is a unicellular organism, and all eukaryotes are multicellular.

• Ribosomes are found in the cytoplasm of the bacterial cell, and eukaryotes do not have ribosomes.

• The bacterial cell has both a cell membrane and a cell wall, and eukaryotes have only cell membranes.

• DNA in the bacterial cell is always in contact with the cytoplasm, and all eukaryotes have DNA located inside a nucleus.

Mammals store extra glucose in the form of a compound called glycogen. Which molecule supplies the energy needed to join glucose molecules together to form a molecule of glycogen?

• ATP

• RNA

• oxygen

• carbon dioxide

Plants in floodplains often get covered by water during floods. Some plants survive the floods because they can continue photosynthesis underwater. However, the plants’ rates of photosynthesis are much lower underwater than above water.

Which of the following helps to explain why the rates of photosynthesis are lower underwater than above water?

• There is too much oxygen in the water

• There is no carbon dioxide in the water

• The chloroplasts do not function under water

• The available light is less intense under water

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:

They do not make their own food.

They each have a nucleus.

They do not have cell walls.

Based on these observations, the organism should be classified as which of the following?

• a plant

• a fungus

• an animal

• a bacteria

The products of photosynthesis are carbohydrates and oxygen. Which process uses these substances as reactants?

• cellular respiration

• fertilization

• mechanical digestion

• translation

A student looks at a cell under a microscope. Which of the following observations would indicate that the cell is from a plant rather than an animal?

• a nucleus located inside of the cell

• numerous cilia on the outside of the cell

• chloroplasts in the cytoplasm of the cell

• a thin membrane around the edge of the cell

In which of the following cell structures are the Drosophila chromosomes located?

• lysosome

• nucleus

• ribosome

• vacuole

A cell membrane has a double layer of molecules. These molecules are made up of a phosphorus-containing “head” and two long, fatty acid “tails.”

Which of the following best explains why the molecules are classified as lipids?

• They contain phosphorus.

• They form a double layer.

• They are made up of fatty acids.

• They are found in the cell membrane.

Maltose is a carbohydrate molecule that provides energy to plants early in their life cycle. Which elements are most common in a molecule of maltose?

• carbon and hydrogen

• copper and nitrogen

• iron and phosphorus

• magnesium and sulfur