Cell replication Flashcards
What happens during mitosis?
Cell duplication in which two daughter cells receive exactly the same nuclear material as the original cell
What are the different phases of interphase?
G1, S1, G2
What happens in the gaps between mitosis and DNA synthesis?
The cells DNA is available for transcription into RNA
The synthesis of the new DNA occurs in what phase?
S phase of interphase
What happens during G1?
The double helix unwinds to expose the bases
During G1 RNA bases pair with…
their complementary partners on the DNA to form the messenger RNA strand
During G1 once an entire gene is copied into the complementary messenger RNA….
the DNA double helix closes and the mRNA exits the nucleus, taking the information it contains to the ribosomes
In the S phase of interphase…
the DNA double helix unwinds with the help of enzymes
What are enzymes…
proteins that increase the speed of reactions
The enzymes during S phase breaks the…
hydrogen bonds between the base pairs and separates the bases from their complementary partners, but does not remove the bases from the backbone of their half of the double helix
During S phase the exposed bases pair…
with new complementary bases tat are then synthesized into a new complementary strand
The new complementary strand during S phase is synthesized with the help of what enzyme….
DNA polymerase
Each of the new two strands of DNA will have…
one strand from the original double helix and one strand that was newly synthesized
What happens during the G2 phase of interphase?
continued protein synthesis and cell growth in preparation for cell division
Mitosis occurs to…
replace old and dying cells with genetically identical ones
Cells that form a new organism via sexual reproduction are called….
gametes
The process by which gametes reduce their DNA content is called….
meiosis
Meiosis occurs only in….
gametes or fertilized eggs
Cells that have two sets of chromosomes are known as…
diploid cells
In mammals, all cells are diploid cells except…
gametes
Cells that contain a single set of chromosomes are known as…
haploid cells
In mammals, only ________ are haploid cells.
gametes
In a diploid cell, each individual chromosome has a twin chromosome called a _________.
homologous chromosome
In mitosis the individual chromosomes duplicate during the….
S phase
In mitosis the individual chromosomes duplicate during the S phase and condense into…
chromosomes that have both copies of the individual chromosomes attached at one spot to form sister chromatids
During metaphase of mitosis chromosomes with their sister chromatids line up on a plate called…
metaphase plate
On the metaphase plate in mitosis what happens?
Spindle fibers form between the centrosomes and attach to the chromosomes on the metaphase plate. Sister chromatids separate and each one moves toward a different centrosome
At the end of metaphase in mitosis….
one chromatid from each chromosome is near each centrosome
When does cytokinesis begin in mitosis?
During anaphase
What is cytokinesis?
separating the two sets of chromosomes into different cells
List steps in mitosis…
Prophase, metaphase, anaphase, telophase
Which phase: spindle fibers form
prophase
Which phase: Centrioles move to opposite sides of the cell
prophase
Which phase: The nuclear membrane disappears
prophase
Which phase: The chromosomes align midway along the spindle fibers
metaphase
Which phase: The chromosomes begin to separate from their daughters
anaphase
Which phase: cytokinesis begins
anaphase
Which phase: spindle fibers disappear
telophase
Which phase: Nuclear membranes reappear
telophase
Which phase: cytokinesis is complete
telophase
In meiotic metaphase the chromosomes are lined up in…
pairs of two homologous chromosomes
In meiotic anaphase what separates?
homologous chromosomes separate but the sister chromatids stay together
The result of meiosis is…
four haploid cells
The result of mitosis is…
two diploid identical cells
