Cell pt 2

Question 1

autotroph vs heterotroph

Answer 1

Auto=produces energy
Hetro=requires energy through food

Question 2

What is the photosynthesis equation

Answer 2

6C02 +6H20 (sunlight and chlorphyll–>) C6H12O6 +6O2
light energy -> chemical energy

Question 3

describe aerobic respiration

Answer 3

breakdown reaction (releasing energy in glucose)
C6H12O6 +6O2 –> 6H20 + 6CO2

Question 4

Anaerobic respiration (fermentation)

Answer 4

plants: Glucose into ethanol + carbon dioxide C6H1206–> 2C2H5OH +2C02
animals: Glucose to lactic acids C6H12O6–>2C3H6O3

Question 5

Describe energy release anaerobic vs aerobic

Answer 5

Aerobic synthesizes 38 ATP molecules

Fermentation can only synthesize 2 ATP molecules because the glucose does not get completely broken down

Question 6

What is ATP

Answer 6

Adenosine tri-phosphate
mobile energy carrier

Question 7

describe ATP -> ADP + Pi

Answer 7

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

Question 8

explain metabolic pathways

Answer 8

chain reaction (enzymes, substrates, products)
small steps: collect intermediary products, regulate heat loss, collect ATP along the way

Question 9

which type of cells undergo mitosis vs meiosis vs binary fission

Answer 9

somatic cells = mitosis
gametes/germ line cells = meiosis
prokaryotes = binary fission

Question 10

Explain why the amount of DNA in a cell doubles before division

Answer 10

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

Question 11

Describe prophase

Answer 11

DNA replication occurs before prophase.
Chromosomes condense + become visible
Spindle fibres assemble + nuclear membrane breaks down

Question 12

Describe meta phase

Answer 12

oChromosomes align at the middle (equator)
Spindle fibres attach to centromere

Question 13

Describe anaphase

Answer 13

Centromeres separate pairs of sister chromatids
Each (single) chromosome is drawn to opposite poles by spindle fibres

Question 14

Describe telophase

Answer 14

Nuclear membrane forms around chromatids
Cells begin to separate
Chromosomes decondense

Question 15

Describe cytokinesis

Answer 15

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

Question 16

diploid vs haploid

Answer 16

Diploid cells contain pairs of homologous chromosomes.
Haploid cells have one chromosome from each homologous pair.

Question 17

describe meiosis

Answer 17

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

Question 18

o Explain why the products of meiosis are haploid cells and contain a single set of chromosomes

Answer 18

Because they are gametes, there are no homologous pairs. Through the division of meiosis, the products are 4 haploid cells

Question 19

Explain the importance of crossing over and independent assortment in meiosis.

Answer 19

variation in gametes

Question 20

how does fertisilisation restore the diploid number

Answer 20

1 gamete = 23 chromosomes (haploid)
zygote = 2 gametes -> restored chromosome number (diploid)

Question 21

Compare the products of mitotic and meiotic cell division.

Answer 21

Mitosis = 2 identical daughter cells, somatic, (46, diploid)
Meiosis = 4 unidentical (unique) daughter cells, gamete (23, haploid)

Question 22

Compare the sources and degree of genetic variation of the products of asexual and sexual reproduction

Answer 22

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

Question 23

Describe the four stages of the cell cycle

Answer 23

G1 is growth by osmosis
S phase semiconservative DNA replication
G2 more growth
Mitosis

Question 24

Describe cell cycle checkpoints

Answer 24

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.

Question 25

Describe internal factors (MPF) for checkpoints 2 and 3

Answer 25

CDK plus cyclin = MPF (mitosis promoting factor) accumulates and reaches threshold for P2
Then Cyclin degrading proteins destory cyclin, causing drop in MPF and triggering end of mitosis.

Question 26

Describe internal and external factors for P1

Answer 26

Internal would be PMF threshold
External would be contact inhibition (Grow hormone receptors blocked by near by cells).

Question 27

What happens when control of the cell cycle is lost

Answer 27

Cells pases through checkpoints unchecked

Rapid uncontrolled cell division

Question 28

Describe application of cell culture example

Answer 28

Skin grafts reduce recovery time by eliminating the need to graft skin from another body part.

Ethical conserves

Question 29

Describe techniques of cell culturing

Answer 29

Glucose
optimal temperature
amino acids
growth factor
sterile conditions

three basic steps: Dissection–> suspension–> Culture