Signals and receptors
Before you read
Test yourself first: 5 questions
Question 1 of 5
Plant cells have a rigid outer structure that animal cells lack, called the:
Answer: B. Plant cells have a cell wall (of cellulose) for support; animal cells have only a cell membrane.
Question 2 of 5
Which structure is found in plant cells but NOT in animal cells?
Answer: B. Plant cells have a rigid cell wall (and chloroplasts) that animal cells lack.
Question 3 of 5
A hypertonic solution around a cell causes the cell to:
Answer: B. Water moves out of the cell toward the higher solute concentration outside, so the cell shrinks.
Question 4 of 5
Which cell process copies a cell to make two identical body cells?
Answer: B. Mitosis produces two genetically identical daughter cells for growth and repair.
Question 5 of 5
When a human body cell divides by mitosis, each new cell has how many chromosomes?
Answer: B. Mitosis produces cells with the full set of 46 chromosomes, identical to the parent cell.
Keep the streak going with more questions like these, each with a full rationale.
Signs & symptoms
- Endocrine — hormones through blood, long distance
- Paracrine — to nearby cells
- Synaptic — neurotransmitter across a synapse
