Chap 8 DNA Replication, Binary Fission, and Mitosis Flashcards
All cells do what?
divide
No living organisms can reproduce without what?
cell division
How do unicellular organisms reproduce?
they divide
Cell division produces what?
a continuous supply of replacement cells in multicellular organisms
What are the parts of the sexual life cycle?
eukaryotic cells divide my meiosis
gametes fuse during fertilization
eukaryotic cells divide by mitosis
What is meiosis?
where each mature individual produces sex cells by another form of cell division (meiosis)
When does meiosis occur?
only during reproduction
Sex cells produced by meiosis contain what?
half the DNA as body cells
What happens in fertilization?
the zygote inherits DNA from both gametes
What are the gametes of humans?
sperm cell
egg cell
What is a zygote?
a fertilized egg
How does a zygote divide?
by mitosis
What does the zygote become after mitosis?
fetus
What are the roles of mitosis?
allow organisms to grow and develop. repair tissue, regenerate lost body parts
Can some organisms reproduce asexually by mitosis?
Yes
What is apoptosis?
cell death
Apoptosis (cell death) can do what?
carve out distinctive structures during development
What are the types of cell division?
binary fission
mitosis
meiosis
What type of cells use binary fission to divide?
prokaryotes
What type of cells use mitosis to divide?
eukaryotes (skin repair, division of a zygote)
What type of cells use meiosis to divide?
production of sex cells (half of the total amount of parent genes)
DNA replication is linked to what?
cell division
Cells must do what before they can divide?
copy/replicate their DNA
What is replicated before division?
the entire genome so each new cell gets one complete copy of the DNA
What replicates DNA?
enzymes
Which enzyme unwinds the DNA?
helicases
Which enzyme synthesizes new DNA strands?
DNA polymerase
Which enzyme join short strands of DNA into long strands?
ligases
What assures that the new DNA strands have the correct sequence?
complementary base pairing
DNA replication is what?
semiconservative
What does semiconservative mean?
the cell keeps the original, parental DNA each time replication takes place, while producing new DNA at the same time
After replication each DNA has what?
one parental strand
one daughter strand
Replication enzymes do what?
divide up the work
DNA replication begins…?
simultaneously at multiple spots along the chromosome called origins of replication
Which direction does replication proceed?
both directions at once from each origin
How do prokaryotes divide?
binary fission
What happens in binary fission?
DNA is replicated and is distributed to two daughter cells
Eukaryotic DNA does what before cell division?
winds up extra tightly
What happens to DNA during replication?
it is unwound
After replication and before the cell starts to divide what happens with the DNA?
it condenses (coils up neatly)
During cell division eukaryotic chromosomes are what?
visible
Before replication DNA is visible as what?
chromatin
Eukaryotic chromosomes are highly what?
condensed DNA
Each chromosome consists of two what?
identical sister chromatids, one for each copy of the replicated DNA
The cells cycle is…?
a repeated series of events
What is the time line of the cell cycle?
the beginning of one cell division until the beginning of the next
The cell cycle includes what?
the time when cells are dividing (mitosis) and the time when cells are not dividing (interphase)
What is M phase?
mitosis
What is eukaryotic cell division?
mitosis
What happens in the M phase?
cells leaving the G2 phase enter mitosis, the division of the nucleus, which is followed by cytokinesis
What is cytokinesis?
the division of the cell itself
What are the steps of the cell cycle?
G1 phase S phase G2 phase prophase metaphase anaphase telophase
Which parts of the cell cycle is part of interphase?
G1 phase
S phase
G2 phase
Which part of the cell cycle is part of mitosis?
prophase
metaphase
anaphase
telophase
What is the G1 phase of the cell cycle?
normal cell function and cell growth
What is the S phase of the cell cycle?
DNA replication
What is the G2 phase of cell division?
additional growth and preparation for division
How many steps are in mitosis?
4 and cytokinesis
mitosis starts with what?
prophase
What is the prophase part of mitosis?
DNA is condensed into chromosomes so two copies of the genome can be separated later
a spindle forms (it is made of microtubules)
What happens once the spindle forms?
chromosomes attach to it
What comes after prophase in mitosis?
metaphase
What happens in metaphase?
chromosomes line up at the equator (this ensures that each cell will receive one copy of each chromosome)
What happens after metaphase in mitosis?
anaphase
What happens in anaphase?
the spindle separates the chromatids (the spindle shortens, moving the sister chromatids toward the opposite centroids)
What happens after anaphase in mitosis?
telophase
What happens in telophase?
chromosomes unwind and spindle dissolves
What happens in cytokinesis?
cytoplasm divides into two new cells
The cell cycle is under tight control?
yes
What regulates the cell cycle?
chemical checkpoints
The chemical checkpoint of the cell cycle check what?
all DNA has replicated
DNA is not damaged
chromosomes line up and separate properly
Cancer cells do what?
divide out of control
In cancer the body loses control of what?
cell division
What do cancer cells do?
continue to divide when they do not need to and override the checkpooints
Treatment does what?
remove or kill abnormal cells
Cancer treatments include what?
surgical tumor removal
anticancer drugs that slow or block cell division
radiation that kills targeted tumor cells
How many chromosomes are there after cytokinesis?
4 (2 in each cell)
