The diagram shows a catalyzed reaction. In the lock-and-key model of enzyme function shown in the diagram, which of the following could NOT be happening in step 3?

What type of carbon based molecule is the first to be broken down by the body's cells to provide a source of energy?

Which of these describes a macromolecule?

Which of these is part of cell theory?

Multicellular organisms use mitosis for growth, development, and _____________.

Which of these shows the correct sequence of events in the cell cycle?

Offspring that are genetically unique are the result of _________.

During which phase of mitosis are chromatids separated?

Mitosis is the process by which ____________________.

How are mitosis and cytokinesis different?

Which event is an important factor in increasing variety among sexually reproducing organisms?

Which phrase best describes the process of meiosis?

Which of these best explains the difference between eukaryotes and prokaryotes?

Which of these shows the greatest degree of hierarchical structural organization?

On a hot day, which of these is an outward sign that thermoregulation is taking place?

Select all that apply. A DNA molecule was evaluated under an electron microscope for its makeup. What is the scientist most likely to find if it is indeed a DNA molecule?

A geneticist used a DNA sequencer to detect the base pair sequencing for a patient. Determine the correct base pairing.

Adenine:_____, Guanine:_____

A strand of mRNA with the sequence GGU CAU UUG will code for which amino acid sequence?

Toby is observing his dog and a houseplant. Which characteristics of life do they share in common? Select all that apply.

Scientists have studied plant and animal cells under a microscope. Which of the following statements have they observed to be true? Select all that apply.

A scientist wanted to investigate what would happen if she transplanted a freshwater plant with an internal concentration of 0.9 g/ml in a salt marsh with a concentration of 15 g/ml. Select the correct answer. What will the scientist observe?

A scientist puts an unknown cell under a microscope. She can see a nucleus, mitochondria, and endoplasmic reticulum. What can she conclude about the cell’s identity?

Select the correct answers. Which of the following elements are most commonly found in living cells? Select all that apply.

Which statement is true?

A frog has a diploid number of 26 chromosomes. How many possible distributions of chromosomes can occur in the homologous pairs of a frog’s gametes?

After fertilization, the embryo develops into a zygote through many cell divisions. If the sperm and egg each contain 8 chromosomes, how many chromosomes are contained within the zygote?

What best describes the results of meiosis in humans?

When recovering from injury, blood platelets that cover the wound are slowly replaced by newly formed skin cells. Old skin cells, with 46 chromosomes, divide to form new skin cells with 46 chromosomes. This is classified as what sort of reproductive process?

If two organisms evolve in response to each other, which evolutionary pattern is demonstrated?

Darwin identified at least 13 different species of finches during his time on the Galapagos Islands. The main difference between the finches was the size and shape of their beaks. Which of the following statements best describes how these differences developed?

Two completely unrelated marine organisms have fins. What term best describes this situation?

A particular species of cave-dwelling fish developed eye sockets and tiny, nonfunctional “eye bulbs”. What word best describes this situation?

During stage I of development, a human embryo, a bat embryo, and a chicken embryo look strikingly similar. What theory does this support?

Natural selection states that individuals

In order to find the best nesting sites and fewest predators, a group of arctic gulls moves further and further north. The birds only begin breeding once they reach their isolated nesting grounds. Over a long time, how would you expect their appearance to change with respect to the original gull population?

Humans have an appendix, a thin tube connected to the large intestine that serves no purpose and is a threat to human health and life if it becomes infected and/or inflamed. It is believed that the appendix once had a function as part of the human digestive system. The human appendix, therefore, is