3 lecture 1 Flashcards
how long does it take a cell to make a peptide bond
about 300 msec
what phase do cells start in
cell starts in g1 (gap 1/gap phase)
what is interphase
g1, s, g2 is collectively called interphase
what is the cell cycle
G1 S G2 Mitosis Cytokinesis
what is Interphase:
the DNA replicates
what is Mitosis:
the copied chromosomes are moved into daughter nuclei
where does mitosis occur
Mitosis occurs in somatic or body cells
what is Cytokinesis
the cell is split into 2 daughter cells
most of the cell cycle is spent in what
interphase
what are the 3 phases of interphase
G1:
S: DNA replicates
G2: cell makes proteins needed to complete mitosis
what happens in g1
cell grows, organelles duplicate
what happens in s
DNA replicates
what happens in g2
cell makes proteins needed to complete mitosis
what does g1 provide
size control
why must growth be controlled
if you don’t have controlled growth in g1, it will look like this
there will be an exponential growth of cells with only a nucleus
you would expect to see (if the growth was to controlled)… she never said what actually happens so…
Before dividing, cells must do what
accurately copy their DNA
what is a gene
is a section of DNA that has the instructions for making a protein
what is a chromosome
One molecule of DNA is wrapped around proteins to form a chromosome
A chromosome has how many genes
100s - 1000s of genes
do all species have the same number of chromosomes
Different species have different numbers of chromosomes
how many chromosomes do human have
we have 46
what are chromosomes before cell division
Chromosomes are uncondensed before cell division
what are duplicated chromosomes
Duplicated chromosomes, held together at the centromere, are called sister chromatids
how are chromosomes duplicated
Chromosomes are duplicated through DNA replication
DNA molecule is split up the middle of what
the helix
what are the steps to DNA replication
Chromosomes are uncondensed before cell division
Duplicated chromosomes, held together at the centromere, are called sister chromatids
Chromosomes are duplicated through DNA replication
DNA molecule is split up the middle of the helix
Nucleotides are added to each side, pairing by hydrogen bonding
Result is two identical DNA molecules, each with one parental strand and one new strand
semiconservative replication
DNA pol moves along the length of the unwound DNA
and helps form
new strands from the template strands
what is DNA polymerase:
is the enzyme that
replicates DNA
DNA replication results in what
DNA replication results in lots of chromosomes that must be efficiently segregated into daughter cells
Mitosis produces what
two genetically-identical nuclei
Mitosis is followed by what
cytokinesis
what is cytokinesis
splits the two nuclei into two daughter cells
what are the 4 stages of mitosis
prophase, metaphase, anaphase, telophase
what happens in prophase
Chromosomes condense
Nuclear envelope disappears
Microtubules pull/push chromosomes
Animal cells: microtubules are attached to centrosomes (which contain centrioles)
centrosomes form the poles of spindle apparatus
what happens in Metaphase
Chromosomes are aligned across the middle of the cell by microtubules
what happens in Anaphase:
centromeres separate (they do not split) sister chromatids are pulled apart toward opposite poles
what happens in Telophase:
Nuclear envelope reforms around the chromosomes
Chromosomes return to uncondensed form
what is cytokinesis
Cytokinesis is the stage in which two daughter cells are formed from the original one
what happens After cytokinesis,
cells re-enter interphase (G1)
what pinches the original cell into two new cells
Proteins (microfilaments; actin) pinch the original cell into two new cells
what does cytokinesis in plants start with
Starts with vesicles forming the cell plate
what is the result of cytokinesis in plants
This results in a new cell wall (made of cellulose) being formed between the cells forming daughter cells
what uses Asexual reproduction
bacteria, some eukaryotes
what is Asexual reproduction
Only one parent
Offspring are genetically identical to parent
what uses Sexual reproduction
animals, plants, fungi
what is produced from sexual reproduction
Gametes are combined from two parents
what are the offspring like compared to their parent in sexual reproduction
Offspring are genetically different from one another and from the parents
