Cell pt 2 Flashcards
autotroph vs heterotroph
Auto=produces energy
Hetro=requires energy through food
What is the photosynthesis equation
6C02 +6H20 (sunlight and chlorphyll–>) C6H12O6 +6O2
light energy -> chemical energy
describe aerobic respiration
breakdown reaction (releasing energy in glucose)
C6H12O6 +6O2 –> 6H20 + 6CO2
Anaerobic respiration (fermentation)
plants: Glucose into ethanol + carbon dioxide C6H1206–> 2C2H5OH +2C02
animals: Glucose to lactic acids C6H12O6–>2C3H6O3
Describe energy release anaerobic vs aerobic
Aerobic synthesizes 38 ATP molecules
Fermentation can only synthesize 2 ATP molecules because the glucose does not get completely broken down
What is ATP
Adenosine tri-phosphate
mobile energy carrier
describe ATP -> ADP + Pi
energy from breakdown reactions is stored in the bonds of ATP molecules (ADP + Pi -> ATP). ATP molecules are converted into ADP + Pi to release the stored energy to be used for synthesis reactions/active processes
explain metabolic pathways
chain reaction (enzymes, substrates, products)
small steps: collect intermediary products, regulate heat loss, collect ATP along the way
which type of cells undergo mitosis vs meiosis vs binary fission
somatic cells = mitosis
gametes/germ line cells = meiosis
prokaryotes = binary fission
Explain why the amount of DNA in a cell doubles before division
The amount of DNA doubles, so that each daughter cell can have the same amount of DNA + identical DNA
this happens in S phase (synthesis phase) of cell cycle
Describe prophase
DNA replication occurs before prophase.
Chromosomes condense + become visible
Spindle fibres assemble + nuclear membrane breaks down
Describe meta phase
oChromosomes align at the middle (equator)
Spindle fibres attach to centromere
Describe anaphase
Centromeres separate pairs of sister chromatids
Each (single) chromosome is drawn to opposite poles by spindle fibres
Describe telophase
Nuclear membrane forms around chromatids
Cells begin to separate
Chromosomes decondense
Describe cytokinesis
Very end/ slightly after mitosis (but we still include it because it sort of finished off the process)
Cytoskeleton + spindle fibres constrict to from a cleavage furrow until the new daughter cells form
diploid vs haploid
Diploid cells contain pairs of homologous chromosomes.
Haploid cells have one chromosome from each homologous pair.
describe meiosis
same as mitosis, but twice also with:
crossing over in prophase 1 - matching section of homologous chromosomes break off and switch
independent assortment: metaphase - homologous pairs randomly assort on equator
o Explain why the products of meiosis are haploid cells and contain a single set of chromosomes
Because they are gametes, there are no homologous pairs. Through the division of meiosis, the products are 4 haploid cells
Explain the importance of crossing over and independent assortment in meiosis.
variation in gametes
how does fertisilisation restore the diploid number
1 gamete = 23 chromosomes (haploid)
zygote = 2 gametes -> restored chromosome number (diploid)
Compare the products of mitotic and meiotic cell division.
Mitosis = 2 identical daughter cells, somatic, (46, diploid)
Meiosis = 4 unidentical (unique) daughter cells, gamete (23, haploid)
Compare the sources and degree of genetic variation of the products of asexual and sexual reproduction
Asexual reproduction = no fertilisation, is genetically identical to parent, very limited genetic variation, only source is random mutation. Very quick, but low levels of variation, methods = binary fission
Sexual reproduction = fertilisation, high levels of genetic variation, slower but that’s okay because you want variation
Describe the four stages of the cell cycle
G1 is growth by osmosis
S phase semiconservative DNA replication
G2 more growth
Mitosis
Describe cell cycle checkpoints
P1 (Just before S phase) Appropriate size and environment and ready for mitosis
P2 (Just before mitosis) Correct DNA replication.
P3 During metaphase if the spindal fibers have attached correctly.
