Unit 4 topics 6-7 ap bio

A cell that has 30 chromatids has how many centromeres?

15

One cell goes through four cell divisions, how many cells would there be after the fourth division?

16

What are diploid cells?

somatic cells that have two sets of chromosomes and divide by mitosis

What are homologous chromosomes?

Two chromosomes (one from mom and one from dad) that are the same length, have the same centromere position, and carry genes controlling the same characteristics

What happens in prophase?

chromatin condenses, nucleoli disappear, sister chromatids appear, mitotic spindle forms, centrosomes move away from each other

What happens in prometaphase?

nuclear envelope fragments, microtubules enter nuclear area

What happens in metaphase?

centrosomes are at opposite poles, chromosomes line up in the middle (metaphase plate), microtubules attach

What happens in anaphase?

sister chromatids separate and move to opposite ends of the cell, cell elongates

What happens in telophase?

two daughter nuclei form

Which cell cycle checkpoint checks for cell size, growth factors, and DNA damage?

G1

If a cell receives the "stop" signal at the G1 checkpoint, what happens to it?

enters a nondividing state called G0

Which cell cycle checkpoint checks for completion of DNA replication and DNA damage?

G2

If a cell receives the "stop" signal at the G2 checkpoint, what happens to it?

attempt to repair damage; may undergo apoptosis

Which cell cycle checkpoint checks for microtubule attachment to chromosomes at the kinetochores?

M (spindle)

How can cancer be caused by defective protein phosphatase?

Cell signaling pathways would be shut down because of the defective protein, and cancer cells would take advantage of this and divide uncontrollably.

Blood glucose

is negative feedback

External cell regulators

Growth factors, contact inhibition, anchorage dependence

Growth factors

Hormones released by cells that stimulate cell growth; CDK’s are activated; imagines signal transduction pathway

Contact (or density) Inhibition

Cell surface receptors recognize contact with other cells; initiates signal transduction pathways that stop the cell cycle in G1 phase

Anchorage dependence

Cells rely on attachment to other cells or extra cellular matrix to divide

How do cancer cells evade those regulators?

Through dna mutations, they do not follow checkpoints and grow infinitely, AND evade apoptosis and continue dividing even w errors

Uncontrollable growth of cancer cells..

Leads to a tumor

Benign tumor

Cells are abnormal but not yet “cancerous” THEY ARE UNABLE TO SPREAD ELSEWHERE IN THE BODY

Malignant tumor

Mass of actual cancerous cells that lose their anchorage dependency and can leave the tumor site

Metastasis

Cells separate from the tumor and spread elsewhere in the body