Studied by 5 peopleA 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
Note
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