AP Bio Unit 4

Front

Long distance signals involving hormones are ________ signals.

Back

endocrine

Front

Which of the following statements best describes negative feedback in homeostasis?

Back

It reduces the output of a system to bring it back to its set point.

Front

How do cell surface proteins, such as MHC proteins and T cell receptors, mediate cell communication over short distances?

Back

The proteins interact directly with proteins on the surfaces of other cells.

Front

What turns off the cell's response in a signal transduction pathway involving a phosphorylation cascade?

Back

protein phosphatases

Front

What type of feedback loop is shown?

Back

positive

Front

Define homeostasis.

Back

Homeostasis is the process by which living organisms regulate their internal environment to maintain stable, constant conditions.

Front

What is the role of hormones in the endocrine system?

Back

Hormones are chemical messengers that travel through the bloodstream to target organs, regulating various physiological processes.

Front

Explain the concept of a feedback loop.

Back

A feedback loop is a biological mechanism whereby a system regulates itself by using the output of a process to control its own activity.

Front

What is the difference between positive and negative feedback?

Back

Positive feedback amplifies changes in a system, while negative feedback reduces output to maintain stability.

Front

What are MHC proteins and their function?

Back

MHC (Major Histocompatibility Complex) proteins are molecules on cell surfaces that present antigens to T cells, playing a crucial role in immune response.