cellular respiration
Aerobic respiration requires what?
C6H12O6 + 6 O2 –> 6 CO2 + 6 H2O + ATP
(glucose + oxygen —> carbon dioxide + water + energy)
This means the cells are most effective at producing ATP when oxygen supply is good.
glycolysis yields what
4 ATP are made for each molecule of glucose but 2 ATP molecules are required to start the process
takes place within the mitochondrial matrix. The process completes the job of breaking down sugar (glucose) and starts by producing only 2 more ATP.
the citric acid cycle
G1
period of cell growth and cytoplasm prep- before the DNA replicates
Homologous Chromosomes
contain the same genes but they may have different variations of those genes, which are called alleles. one homologous chromosome is obtained from each parent
What is cytokinesis?
occurs at the end of mitosis and is a division of the cytoplasm into roughly equal halves.
in animals, it occurs by actin filaments contracting and pinching the cell in two - the action is evident as a cleavage furrow that appears between daughter cells.
surrounded (encapsulated) by a healthy layer of cells and do not spread to other areas.
Why does meiosis occur?
to produce gametes (sperm or eggs)
Gametes are haploid cells (have half the normal amount of DNA)
Prophase 1
homologues pair up and exchange segments
Cellular respiration takes place in two stages named?
Glycolosis (splitting of glucose) and the Krebs cycle (3 steps)
What organisms are capable of carrying out glycolysis?
all organisms
takes place in the inner mitochondrial membrane and produces the vast majority of ATP (up to 34 produced). It uses a series of redox reactions to produce the ATP.
The Electron transport chain
S
Period when DNA replicates and chromosomal proteins are duplicated (chromosomes not condensed)
IMPORTANT
Sister chromatids
are exactly the same and are a result of DNA replication
What is prophase?
-Condensed chromosomes first become visible
-the nuclear envelope begins to disintegrate
-the nucleolus disappears
-centrioles separate in the centre of the cell and migrate to opposite end (“poles”) of the cell.
What is cancer?
A growth disorder of cells
-begins when apparently normal cells grow uncontrollably and spread to other parts of the body
what cells undergo meiosis?
Germ cells in the testis or ovary (in mammals)
Prophase 2
after a brief interphase with no DNA replication, new spindle fibres form
What are the steps of the Krebs cycle
Transition step
citric acid cycle
electron transport chain
This biochemical process was probably what
the earliest to evolve
The movement of the split glucose and oxygen into the mitochondria (uses ATP) is known as?
transitions step (does not produce ATP)
G2
Period of cell growth and organelle preparation- after replication
An arrangement of chromosomes is called what
a karyotype
What is interphase?
-Sets the stage for cell division
-chromosomes are first duplicated
-although not visible, chromosomes begin to wind up tightly in a process called Condensation.
Cancerous cells that spread to other areas of the body are called what
metastases
What is the result of meiosis in humans?
sperm and eggs are the result. sperm fertilizes an egg to produce a zygote
Telophase 2
individual chromosomes gather at each of the two poles and a new nuclear envelope forms
Where does glycolysis occur?
in the cytoplasm
This is the only was organisms can derive what
energy from food in the absence of oxygen (anaerobic- no oxygen needed)
G0
Cell cycle arrest
Chromosomes can be compared based on what
size, shape and centromere location
-each cable in the spindle is made of microtubules
-these microtubules grow from each pole until attached to a centromere at a disc of protein called a kinetochore
tumours that are not encapsulated and are invasive.
-cells from malignant tumours leave and spread to different areas of the body to form new tumours
Meiosis is replicated before which?
meiosis 1
Metaphase 1
the paired homologous chromosomes align at the equatorial plane
Glycolysis is what?
Is a sequence of chemical reactions that break one glucose molecule (six carbons) into two pyruvate molecules (three carbons)
the breaking of bonds is used to form 2 ATP and is called phosphorylation
M phase
prophase, metaphase, anaphase, telophase and cytokinesis
Pass Me A Taco Chef
A karyotype of human chromosomes would show how many?
23 pairs of Chromosomes or 46 chromatids
What is anaphase?
Sister chromatids separate - enzymes break the cohesin and kinetochores
the microtubules of the spindle are dismantled, staring at the poles - this pulls the chromatids toward the poles.
What is a tumor
a growing cluster of cells
Meiosis 1 involves?
Separating the homologous pairs
Telophase 1
individual chromosomes gather at each of the two poles
What is phosphorylation?
the process of adding a phosphate to ADP
What is telophase?
a nuclear envelope forms around the set of chromosomes at each pole
the chromosomes begin to become uncondensed
the nucleolus reappears
Cancer results from what
damaged genes failing to control cell division
Meiosis 2 involves?
Separates the sister chromatids
Anaphase 1
homologues separate from the pairing and move to opposite poles
What is metaphase?
-the chromosome attached to microtubules of the spindle are aligned in the centre of the cell
-the centromeres are aligned along an imaginary plane that divides the cell in half; this is known as the equatorial plane.
One such gene, p53, affects the G1 checkpoint. what is the normal action of this checkpoint?
it’s normal action is to detect abnormal DNA
-it prevents cell division of a cell with damaged DNA until the DNA is repaired, or it directs the cell to be destroyed if the damage cannot be fixed.
What happens when meiosis is complete?
the result is that one diploid cell has become one haploid egg or four haploid sperm
Anaphase 2
sister chromatids separate from the pairing and move to opposite poles
differences in mitosis from meiosis?
One 2n cell produces 2 identical 2n daughter cells
Mechanisms help produce?
variety, genetic variation
-crossing over (called recombination after it happens)
Involves switching DNA between homologous pairs —> amount sister chromatids
Metaphase 2
the sister chromatids align at the equatorial plane
What is independent assortment?
involves the random movement of chromosomes to different sides of the cell dividing —> one goes left, one goes right (no pattern)
Differences in meiosis from mitosis?
All events unique to meiosis occur in meiosis 1 (that is the homologous pairs do not separate) (crossing over occurs)
one 2n cell produces 4 haploid (n) cells. These carry different packets of information