Chapter 8 Flashcards
What steps occur in a sexual life cycle?
Mitosis, meiosis, and fertilization.
What happens in sexual reproduction?
2 parents produce genetically variable gametes by meiosis. Fertilization produces a zygote.
Mitosis cell division produces identical eukaryotic cells used for what?
Growth, tissue repair, and asexual reproduction.
What is apoptosis?
Programmed cell death
What does apoptosis do?
Shapes structures and kills cells that could become cancerous.
What happens after the cell receives the signal to die?
Enzymes destroy the cell’s components. Immune system cells dispose of the remains.
What is necrosis?
Cell death due to trauma or infection.
Prophase
chromosomes are condensing and the spindle fibers start to form
Prometaphase
nuclear envelopes begin to break down and spindle fibers attach to kinetochores at the centrosome
Metaphase
replicated chromosomes align along cells center
Anaphase
chromatid of each replicated chromosomes seperate
Telophase
the spindle fibers break down and nuclear envelopes form
What does a contractile ring form?
cleavage furrow (the indentation of the cell’s surface that begins the progression of cleavage)
What forms as plant cells divide between two daughter cells?
cell plate
How does cancer arise?
when cells divide out of control
What regulates cell division?
chemical signals
What stimulates cell division that may pause or halt at multiple check points during the cell cycle?
external signals called growth factors
When does DNA Replication happen?
before cell division (mitosis) during interphase
Dividing cells must 1st do what?
duplicate its genome which consists of 1 or more chromosomes
Helicase enzymes do what?
unwind and unzip DNA
What keeps strands seperate?
binding proteins
__ adds DNA nucleotides to RNA primer.
DNA polymerase
What seals nicks after the primer is replaced with DNA ?
Legase
What do DNA replication errors produce?
mutations
How do prokaryotes divide?
binary fission
Step 1 of binary fission:
DNA first replicates
Step 2 of binary fission:
2 chromosomes attach to the cell membrane
Step 3 of binary fission:
cell growth between the attachment points separates the chromosomes into 2 identical daughter cells
Replicated chromosomes do what as a eukaryotic cell prepares to do divide?
condense
What does a chromosome consist of?
chromatin (DNA+protein)
Where are the 2 identical sister chromatids of a chromosome attached?
to the centromere
How is chromatin organized?
in nucleosomes
How can tumors occur?
from excess cell division or deficient apoptosis
Cancer cell break through cell cycles. True or false
true
Do benign tumors spread?
no
Does a malignant tumor spread?
yes, by invading nearby tissues and metastasizes if it reaches the bloodstream
What is cancer?
a family of diseases characterized by malignant cells.
How do cancer cells divide?
uncontrollaby
What happens when telamere becomes very short?
divison ceases
Cancer cells produce an enzyme called?
telamerase (angiogenic factors)
Cancer cells continue to divide even after growth factors depleted. True or false
true
