Chapter 9,16.3 Study Guide Flashcards
Mitosis
Why is cell division necessary? What are the 3 situations in which cell division occurs?
It helps life continue. Functions in reproduction, growth, and repair
Reproduction in cell division
division of unicellular, reproduces an organism
growth in cell division
enables multicellular organism to develop from egg
repair in cell division
repair and renew cells that die from wear and tear
genome
cell’s DNA, genetic infoC
Chromosomes
hold genome, long linear DNA
How much DNA does one chromosome contain?
46 DNA (23 mom, 23 dad) with multiple genes
Chromatin
made up of DNA, RNA, and proteins and forms chromosomes
somatic cells
all cells in an organism except for reproductive
gametes
eggs or sperm
homologous chromosomes
a pair of chromosomes that are similar in size, shape, and genetic information, but are not identical (mother and fathers)
sister chromatids
identical copy of one of the DNA molecules (still 1 chromosome) replicated chromosomes, identical
What is the longest phase in the cell cycle? Why?
Interphase, because it contains G1, S, and G2
What happens in G1
growth phase, organelles, nutrients, general preparation of cell
S phase
DNA replication
G2 Phase
Growth, double checks that the replicated DNA is ready for mitosis
M phase
division of the nucleus of cell (not cytoplasm)
What does G1 checkpoint check for?
unduplicated chromosomes, determines if the cell is ready to divide
Prophase
chromatin coil and compact, forming visible chromosomes or x shaped sister chromatids, centrosomes go to opposite sides of the cell
Metaphase
all the replicated chromosomes line up in the middle of the cell, nuclear membrane is gone
Anaphase
the sister chromatids of each chromosome separate at the centromere and are pulled apart by the spindle fibers creating double the amount of chromosomes, moving towards opposite poles of the cell, distributing identical copies of genetic material to the future daughter cells
Telophase
the chromosomes reach the poles of the cell, a nuclear membrane reforms around each set of chromosomes, the spindle fibers disassemble, and the chromosomes begin to decondense
cytokinesis
the cytoplasm of a single cell is physically divided into two separate daughter cells
difference in eukaryotic and prokaryotic cell division
eukaryotic involves mitosis or meiosis, mitosis produces 2 identical daughter cells, prokaryotic involves binary fission to produce the 2 identical daughter cells
During mitosis, eukaryotes ____ _____ breaks to allow spindle to attach to chromosomes. However with prokaryotes, DNA is _____ ( )
nuclear envelope, directly accessible (no envelope)
In eukaryotic cytokinesis occurs in___
In prokaryotic cytokinesis occurs in ___
cleavage furrow, cell plate
What is a prokaryotes mode of reproduction, eukaryotes?
binary fission, sexually through meiosis and gamete fusion, and asexually through mitosis
how many chromosomes does a prokaryotic cell have? shape?
one chromosome, single circular DNA molecule
How many chromosomes does a eukaryotic cell have? shape?
46 chromosomes 23 pairs, long linear straight strands of DNA
G1 checkpoint checks for?
that cell is ready for DNA replication, before S phase, enough nutrients? DNA undamaged?
G2 checkpoint checks for?
before mitosis, makes sure it is ready to divide, was it replicated properly? healthy?
M checkpoint checks for
during metaphase, ensures chromosome allignment before chromosomes are separated into daughter chromosomes
Tumor supressor “___” does what
p53; normally regulate cell cycle and limit growth or division, promote apoptosis, can halt the cycle at g1/sphase and allow dna time to repair
what has to happen in order for p53 to cause cancer?
both copies need to be missing, when p53 is damaged or missing, it can’t kill cancer cells, so they replicate
Proto-oncogenes “___” do what?
ras; normal functioning gene, become oncogenes when mutated, oncogenes can cause cancer when introduced into the cell and can become hyperactive
how can ras cause cancer
one mutated ras gene, mutated gene continues to spread
Describe estrogen, progesterone, and HER2 receptors involvement in development of breast cancer
Breast cancer tumors show high amounts of HER2, which also show an increase in the number of estrogen receptor molecules that can trigger cell division.
What does chemotherapy do for breast cancer?
Herceptin binds to the HER2 receptor and prevents it from pairing w/ other HER2, this leads to a decreased activation of downstream signaling, which can lead to apoptosis
how do chemotherapy drugs impact mitosis
inhibition of microtubule function (can’t separate chromosomes during anaphase), inhibition of DNA synthesis (cause breaks in DNA or prevents replication S phase),
main difference in tumor suppressors and oncogenes
tumor suppressors repair DNA or can initiate apoptosis while oncogenes are a mutated version of proto-oncogenes that are overactive, tumor suppressors are recessive meaning both copies have to be mutated for it to cause harm, oncogenes are dominant meaning one mutated gene would cause harm
