Unit 4 check
Unit 4 check: Cell Communication and Cell Cycle
10 questions from 6 lessons in Unit 4. Answer each one, and if you miss, follow the link back to where it is taught, then try again. Your score counts first tries.
Question 1 · from 4.1 · Fill the statement
Complete the description of two cells signaling by direct contact.
In a leaf, channels through the cell walls join the of neighboring cells, so a signal molecule passes straight into the next cell. In the body, an immune cell recognizes another cell by binding molecules on that cell's . In both cases the signal does not have to .
Question 2 · from 4.2 · Put it in order
A hormone binds a G protein-coupled receptor. Put the events in the order they happen.
Question 3 · from 4.3 · Fill the statement
Complete the description of a pathway with a mutant kinase that cannot work.
The ligand still binds and the receptor still changes shape, because those steps come the kinase. The steps the kinase stop, so the cell's does not happen.
Question 4 · from 4.4 · Multiple choice
A person's pancreas releases very little insulin. Which change in blood glucose after a meal is most likely?
Setup for question 5
A new experiment. A student treats onion root tips with a chemical that stops spindle fibers from pulling chromatids apart. She counts 200 cells in an untreated tip and 200 cells in a treated tip. These numbers are a teaching example.
- Untreated: interphase 160, prophase 20, metaphase 8, anaphase 4, telophase 8
- Treated: interphase 136, prophase 18, metaphase 46, anaphase 0, telophase 0
Question 5 · from 4.5 · Calculate
What percentage of the cells in the treated tip are in metaphase?
Setup for question 6
A new experiment. A researcher exposes two kinds of cells to radiation that damages DNA, then follows them for 12 hours. The mutant cells lack a protein that the cell's DNA-damage checkpoints need. These numbers are a teaching example.
- Normal cells: 4% enter mitosis, and 30% undergo apoptosis
- Mutant cells: 56% enter mitosis, and 3% undergo apoptosis
Question 6 · from 4.6 · Decide and justify
Do these data support the claim that the mutant cells' checkpoints fail to stop cells with damaged DNA?
Which evidence supports your decision?
Question 7 · from 4.1 · Multiple choice
A neuron releases a neurotransmitter into the narrow gap between it and a muscle cell. That muscle cell contracts, but muscle cells elsewhere in the body do not. Which statement best explains why?
Question 8 · from 4.2 · Multiple choice
In a signaling cascade, each activated protein activates many molecules of the next protein. What is the main effect of this on the cell's response?
Question 9 · from 4.3 · Match
Each chemical acts on one component of a pathway. Match each chemical to the result it would cause.
Setup for question 10
A new situation. During labor, a midwife records how many contractions happen in each 10 minutes, once an hour. Blood tests show oxytocin rising each hour too. These numbers are a teaching example.
- Hour 1: 2 contractions in 10 minutes
- Hour 2: 3 contractions
- Hour 3: 5 contractions
- Hour 4: 8 contractions
Question 10 · from 4.4 · Calculate
By what percentage did the number of contractions in 10 minutes increase from hour 1 to hour 4?
0 of 10 answered.