Ch 9,10,12,13

Question 1

Cell division:

Answer 1

The continuity of life is based on the reproduction of cells.

Integral part of cell cycle.

Passing identical genetic material to cellular offspring is a crucial fxn.

Question 2

Cell cycle:

Answer 2

The life of a cell from the time it is first formed during division of a parent cell until its own division into two daughter cells.

Question 3

Genome:

Answer 3

A cell’s endowment of DNA, its genetic information.

Prokaryotic cells- have 1 single DNA molecule.

Eukaryotic cells- have a number of DNA molecules.

Question 4

Chromosomes:

Answer 4

DNA molecules are packaged into structures called chromosomes.

Eukaryotic chromosomes have 1 very long linear DNA molecule associated with many proteins.

Associated proteins maintain the structure and help control the activities of genes.

Question 5

Chromatin:

Answer 5

Together, the entire complex of DNA and proteins that is the building material of chromosomes.

Varies in its degree of condensation during the process of cell division.

Question 6

Somatic cells:

Answer 6

All body cells except the reproductive cells.

Human somatic cells each contain 46 chromosomes, made up of 2 sets of 23, one from each parent.

Question 7

Gametes:

Answer 7

Reproductive cells- sperm and eggs.

Have one set, or half as many chromosomes as somatic cells.

Question 8

Sister chromatids:

Answer 8

Each duplicated chromosome has 2 sister chromatids.

Joined copies of the original chromosome.

Each contain identical an DNA molecule.

Initially attached along their lengths by protein complexes called cohesins, aka sister chromatid cohesion.

Question 9

Centromere:

Answer 9

A region of the chromosomal DNA where the chromatid is attached most closely to its sister chromatid.

Mediated by proteins bound to the centromeric DNA, other bound proteins condense the DNA, giving it a narrow waist.

Question 10

Mitosis:

Answer 10

The division of the genetic material in the nucleus, usually followed by cytokinesis.

Question 11

Cytokinesis:

Answer 11

After mitosis, the division of the cytoplasm, well underway by late telophase.

One cell has become 2, each the genetic equivalent of the parent cell.

In animal cells, involves formation of cleavage furrow, which pinches cell in 2.

Question 12

Mitotic (M) phase:

Answer 12

Includes both mitosis and cytokinesis, usually the shortest part of the cell cycle.

Alternates with interphase.

Question 13

Interphase:

Answer 13

Often accounts for about 90% of the cycle.

Subphases:

• G1 phase (first gap)
• S phase (synthesis)
• G2 phase (second gap)

Cell grows in all 3 phases but the chromosomes are duplicated only during the S phase.

Question 14

Meiosis:

Answer 14

A variation of cell division I which you produce gametes-sperm or egg.

Yields daughter cells with only one set of chromosomes, half as many as parent cells.

Reduces number of sets of chromosomes from 2 to 1 in gametes, counterbalancing the doubling that occurs at fertilization.

Question 15

Mitosis is broken down into 5 stages:

Answer 15

1. Prophase
2. Prometaphase
3. Metaphase
4. Anaphase
5. Telophase/ cytokinesis

Question 16

Mitotic spindle:

Answer 16

Many events of mitosis depend on this, which begins to form in the cytoplasm during prophase.

A structure made of microtubules that controls chromosome movement during mitosis.

Question 17

G2 of Interphase:

Answer 17

Nuclear envelope encloses nucleus.

Nucleus has 1 or more nucleoli.

Single centrosome has duplicated, become 2. Each centrosome has 2 centrioles.

Chromosomes, duplicated during S phase, cannot be seen yet becuz they haven’t been condensed.

Question 18

Centrosome:

Answer 18

In animal cells, starts the assembly of spindle microtubules.

A subcellular region containing material that functions throughout the cell cycle to organize the cell’s microtubules.

Microtubule organizing center.

Pair of centrioles are located at the center, not essential for cell division, also not present in plant cells.

Question 19

Aster:

Answer 19

A radial array of short microtubules, extends from each chromosome.

Question 20

Kinetochore:

Answer 20

A structure made up of proteins that have assembled on specific sections of DNA at each centromere.

Face opposite directions.

Each of the two sister chromatids of a duplicated chromosome has a kinetochore.

Question 21

Metaphase plate:

Answer 21

Imaginary plate rather than an actual cellular structure.

Question 22

Cleavage:

Answer 22

In animal cells, cytokinesis occurs by a process called cleavage.

First sign of cleavage is the appearance of a cleavage furrow.

Question 23

Cleavage furrow:

Answer 23

A shallow groove in the cell surface near the old metaphase plate.

On cytoplasmic side the furrow is a contractile ring of actin microfilaments, which interact with myosin molecules, causing ring to contract.

The cleavage furrow deepens until parent cell is pinched in two, making 2 separate cells each with its own nucleus and own share of cytosol, organelles, and other subcellular structures.

Plant cells have no cleavage furrow.

Question 24

Cell plate:

Answer 24

In plant cells, there is no cleavage furrow. Instead, in telophase, vesicles from Golgi apparatus move along microtubules to middle of cell where they coalesce, making the cell plate.

Cell wall materials carried on vesicles collect inside cell plate as it grows.

Cell plate enlarges until its surrounding membrane fuses with plasma membrane along perimeter of cell.

Making 2 daughter cells, each with own plasma membrane. New cell wall between.

Question 25

Binary fission:

Answer 25

Division in half. Prokaryotes can undergo type of reproduction in which cells grow to roughly double size, then divides to form 2 cells. Also refers to Asexual reproduction of single- celled eukaryotes.

Question 26

Origin of replication:

Answer 26

DNA of bacterial chromosome begins to replicate at this specific place on chromosome. Produces 2 origins. As chromosome continues to replicate, one origin moves rapidly toward the opposite end of cell. Cell elongates, while chromosome is replicating. After replication, bacterium is twice its size, plasma membrane pinches inward, making division into 2 daughter cells.

Question 27

Cell cycle control system:

Answer 27

A cyclically operating set of molecules in the cell that both triggers and coordinates key event in the cell cycle.

Question 28

Checkpoint:

Answer 28

A control point in the cell cycle where stop and go-ahead signals can regulate the cycle. 3 important checkpoints are found in the: - G1 phase - G2 phase - M phase

Question 29

Cyclin:

Answer 29

A protein that gets its name from it cyclically fluctuating concentration in the cell.

Question 30

Cyclin- dependent kinases, or Cdks:

Answer 30

The activity of Cdk rises and falls with changes in the concentration of it cyclin partner.

Question 31

MPF:

Answer 31

Stands for maturation- promoting factor, aka. M-phase-promoting factor. The cyclin-Cdk complex that was discovered first (in frog eggs). Peaks of MPF activity correspond to the peaks of cyclin concentration. Triggers cell's passage into the M phase past the G2 checkpoint.

Question 32

G0 phase:

Answer 32

Nondividing state. Most cell's in the human body are in this phase. Mature nerve and muscle cells never divide. Other cells (liver) can be called back from this phase to cell cycle by external cues, such as growth factors released during injury.

Question 33

Growth factor:

Answer 33

A protein released by certain cells that stimulate other cells to divide. Different cell types reaping specifically to different growth factors or combinations of growth factors.

Question 34

Density-dependent inhibition:

Answer 34

Phenomenon in which crowded cells stop dividing. If cells are removed, those bordering the open space begin dividing again and continue until space is filled.

Question 35

Anchorage dependence:

Answer 35

Most animal cells exhibit this. To divide, they must be attached to a substratum, such as inside a culture flask or the extracellular matrix of a tissue. Signaled to the cell cycle control system via pathways involving plasma membrane proteins and element of the cytoskeleton linked to them.

Question 36

Transformation:

Answer 36

Cells in culture that acquire the ability to divide indefinitely have undergone transformation. The process that causes them to behave like cancer cells.

Question 37

Benign tumor:

Answer 37

The abnormal cells may remain at the original site if they have too few genetic and cellular changes to survive at another site. Do not cause serious problems and can be removed by surgery.

Question 38

Malignant tumor:

Answer 38

Cells whose genetic and cellular changes enable them to spread to new tissues and impair the functions of one or more organs. Also called transformed cells. Individual with this has cancer.

Question 39

Metastasis:

Answer 39

A few tumor cells may separate from the original tumor, enter the blood vessels and lymph vessels, and travel to other parts of the body. Where it may proliferate and form a new tumor. Spread of cancer cells to locations distant from original site .

Question 40

Cellular Respiration (products and reactions):

Answer 40

C6H12 + 6O2 --> 6CO2 + 6H2O + ATP

Question 41

Glycolysis inputs:

Answer 41

C6 H12 O6 2 ATP 2 NAD+ 4 ADP + 4P

Question 42

Glycolysis outputs:

Answer 42

2 NADH 4 ATP (2 NCT ATP) 2 Pyruvates

Question 43

Pyruvate oxidation inputs:

Answer 43

2 Pyruvate 2 NAD+ 2 Coenzyme A

Question 44

Pyruvate oxidation outputs:

Answer 44

2 CO2 2 NADH 2 Acetyl CoA

Question 45

Citric Acid Cycle inputs:

Answer 45

2 Acetyl CoA 6 NAD+ 2 FAD

Question 46

Citric Acid Cycle outputs:

Answer 46

6 NADH 4 CO2 2 ATP 2 FADH2

Question 47

Mitosis (list in v.):

Answer 47

1. Growth, development, repair, and asexual reproduction. 2. One parent cell --> 2 daughter cells 3. 2N (diploid) parent cell --> 2N daughter cell 4. 1 division 5. Daughter cells are genetically identical to parent cell and each other. 6. No crossing over or genetic recombination.

Question 48

Meiosis (list in v.):

Answer 48

1. Make gametes (sperm and eggs). 2. One parent cell --> 4 daughter cell 3. 2N parent cell --> 1N (haploid) daughter cells 4. 2 Divisions 5. Daughter cells are NOT genetically identical to parent cells or each other. 6. Crossing Over and Genetic Recombination

Question 49

Photosynthesis (products and reactants):

Answer 49

Light | 6 CO2 + 6 H2O ---> C6 H12 O6 + 6O2

Question 50

Cellular Respiration process (steps):

Answer 50

1. Glycolysis (anaerobic) 2. Pyruvate Oxidation (aerobic) 3. Citric Acid Cycle (aerobic) 4. Oxidation Phosphorylation a) Electron transport chain b) Chemiosmosis

Question 51

Glycolysis:

Answer 51

In Cytoplasm (cytosol). Breaks glucose down into 2 molecules of Pyruvate.

Question 52

Pyruvate Oxidation:

Answer 52

In matrix. In eukaryotes, Pyruvates enter mitochondrion and is oxidized to a compound called Acetyl CoA.

Question 53

Citric Acid Cycle:

Answer 53

In matrix. Acetyl CoA enters. Breakdown of Glucose to CO2 is completed.

Question 54

Oxidation Phosphorylation:

Answer 54

On cristae. Accounts for 90% of ATP generated. ADP converts to ATP using energy released. It is powered by redox reactions of electron transport chain. Energy released at each step of the electron transport chain is stored in a form the mitochondrion (or prokaryotic cell) can use to make ATP from ADP.

Question 55

Electron Transport Chain:

Answer 55

Accepts electrons (via NADH), passes electrons from one molecule to another.

Question 56

Chemiosmosis:

Answer 56

Thru ATP synthase. Process in which energy stored as H+ gradient across a membrane and is used to drive cellular work, such as synthesis of ATP.

Question 57

Substrate-level phosphorylation:

Answer 57

ATP synthesis occurs when enzyme transfers a phosphate group from a substrate molecule to ADP, instead of adding an inorganic phosphate to ADP.

Question 58

Karyotype:

Answer 58

A display of condensed chromosomes arranged in pairs, starting with the longest chromosome.

Question 59

Homologous chromosomes (homologous):

Answer 59

Two chromosomes of a pair have the same length, centromere position, and staining pattern Both chromosomes of each pair carry genes controlling the same inherited characters.

Question 60

Asexual reproduction:

Answer 60

Offspring are exact genetic copies of themselves (clones). A single individual is the sole parent and passes copies of genes without fusion of gametes. Reproduce by mitotic cell division, in which DNA is copied and given equally to 2 daughter cells. Genetic differences occasionally arise as a result of a change in DNA called mutations.

Question 61

Sexual Reproduction:

Answer 61

2 parents make offspring that have unique combinations of genes inherited by parents. Offspring vary genetically from siblings, and both parents. Variation on common theme of family resemblance, not exact replicas.

Question 62

Prophase:

Answer 62

Chromatin fibers coil and condense to form chromosomes. Nucleoli disappear. Each duplicated chromosome look like 2 sister chromatids joined at their centromeres. Mitotic spindle begins to form, made of the centrosomes and microtubules that extend from them. Radial arrays of shorter microtubules extending from centrosomes are called asters. Centrosomes move away from each other, pushed partly by lengthening microtubules between them.

Question 63

G2 of Interphase:

Answer 63

Nuclear envelope encloses nucleus, which contains 1+ nucleoli. 2 centrosomes have formed, duplicated by single centrosome. Each centrosome has 2 centrioles. Chromosomes (created during S phase) cannot be seen individually, because they haven't condensed.

Question 64

Prometaphase:

Answer 64

Nuclear envelope fragments. Centrosome extending microtubules can invade nuclear area. Chromosomes have become more condensed. Each of the 2 chromatids of each chromosome now has a kinetochore. Some microtubules connect to kinetochore, kinetochore microtubules, which jerk chromosomes back and forth. Nonkinetochore microtubules interact with those from opposite pole of spindle.

Question 65

Metaphase:

Answer 65

Centrosomes are now at opposite poles of cell. Chromosomes have all arrived at metaphase plate, a plane that is equidistant between spindle's 2 poles. Chromosomes centromere's lie at metaphase plate. For each chromosome, kinetochores of sister chromatids are attached to kinetochore microtubules coming from opposite poles.

Question 66

Anaphase:

Answer 66

Shortest stage of mitosis, lasting few mins. Begins when cohesion proteins are cleaved. 2 sister chromatids part suddenly. Each chromatid becomes a chromosome. 2 daughter chromosomes move toward opposite ends of cell as their kinetochore microtubules shorten. Cell elongates as kinetochore microtubules lengthen. In the end, 2 ends of cell have equal and complete set of chromosomes.

Question 67

Telophase:

Answer 67

2 daughter nuclei form in cell. Nuclear envelopes come from fragments of parent cell's nuclear envelope and other parts of endomembrane system. Nucleoli disappear. Chromosomes become less condensed. Remaining spindle microtubules are depolymerized. Mitosis is now complete.

Question 68

Sex chromosomes:

Answer 68

Determine an individual's sex. X and Y chromosomes.

Question 69

Autosomes:

Answer 69

All other chromosomes (not X or Y, which determine sex)

Question 70

Diploid cell:

Answer 70

Any cell with 2 chromosome sets. Abbreviated as 2n. For humans, there are 46 (2n=46), the number of chromosomes in our somatic cells. A zygote.

Question 71

Haploid cells:

Answer 71

Gametes contain a single set of chromosomes. For humans, the haploid number is 23 (n=23). Set of 23 consists of 22 autosomes plus a single sex chromosome. Sperm or egg.

Question 72

Interphase of meiosis:

Answer 72

Pair of homologous chromosomes in diploid parent cell. Chromosomes are duplicated. 2 sister chromatids in a diploid cell.

Question 73

Prophase 1 in meiosis:

Answer 73

Centrosome movement, spindle formation, nuclear envelope breakdown. Chromosomes condense progressively thru out prophase 1. Each chromosome pairs with its homolog, aligned gene by gene, and crossing over occurs. Each homologous pair has 1+ x-shaped regions called chiasmata. One of the microtubules attaches to 2 kinetochores, one at the centromere of each homolog, and then will move toward the metaphase plate.

Question 74

Metaphase 1 in meiosis:

Answer 74

Pairs of homologous chromosomes are now arranged at metaphase plate, with one chromosome in each pair facing each pole. Both chromatids of one homolog are attached to kinetochore microtubules from one pole. Those of other homolog are attached to microtubules from opposite pole.

Question 75

Anaphase 1 in meiosis:

Answer 75

Breakdown of proteins responsible for sister chromatid cohesion along chromatid arms allow homologs to separate. Homologs move toward opposite poles, guided by spindle apparatus. Sister chromatid cohesion persists at centromere, making chromatids move as a unit toward same pole.

Question 76

Telophase 1 and Cytokinesis in meiosis:

Answer 76

Each half of the cell has complete haploid set of duplicated chromosomes. Each chromosome is made of 2 sister chromatids, one or both chromatids have regions of nonsister chromatid DNA. Cytokinesis occurs simultaneously with telophase 1, making 2 haploid daughter cells. In animal cells a cleavage furrow forms, in plant cells a cell plate forms. In some species, chromosomes condense and nuclear envelopes form. No chromosome duplication occurs between meiosis 1 and meiosis 2.

Question 77

Prophase 2 in meiosis:

Answer 77

Spindle apparatus forms. Chromosomes still composed of 2 chromatids associated at centromere, move toward the metaphase 2 plate.

Question 78

Metaphase 2 in meiosis:

Answer 78

Chromosomes are positioned at metaphase plate. Because of crossing over in meiosis 1, the 2 sister chromatids of each chromosome are NOT genetically identical. Kinetochores of sister chromatids are attached to microtubules extending from opposite poles.

Question 79

Anaphase 2 in meiosis:

Answer 79

Breakdown of proteins holding sister chromatids together at centromere allows chromatids to separate. Chromatids move toward opposite poles as individual chromosomes.

Question 80

Telophase 2 and Cytokinesis in meiosis:

Answer 80

Nuclei form, chromosomes begin de condensing, and cytokinesis occurs. Meiotic division of one parent cell produces four daughter cells, each with haploid set of (unduplicated) chromosomes. Four daughter cells are genetically distinct from one another and from parent cell.

Question 81

Crossing over:

Answer 81

Occurs in prophase 1 of meiosis. The DNA molecules of non-sister chromatids are broken (by proteins) and are rejoined together.

Question 82

Chiasmata:

Answer 82

X-shaped region, where crossovers have occurred. Hold homologs together as spindle forms for first meiotic division.

Question 83

When do homologous chromosomes separate?

Answer 83

Breakdown of proteins during Anaphase 1 of meiosis. Duplicated chromosomes of each homologous pair move toward opposite poles. Sister chromatids of each duplicated chromosome remain attached.

Question 84

When do sister chromatids separate?

Answer 84

Two steps in meiosis: one at start of Anaphase 1 and at Anaphase 2. In mitosis, it starts at end of Metaphase, when enzymes cleave cohesins

Question 85

Synapsis:

Answer 85

Formation of a zipper-like structure holds one homolog tightly to the other. During this, the DNA breaks are closed up so that each broken end is joined to the corresponding segment of the non-sister chromatid. Paternal chromatid is joined to a maternal chromatid beyond the crossover point (vice versa).

Question 86

Independent assortment:

Answer 86

Because each pair of homologous chromosomes is positioned independently of other pairs at metaphase 1, the first meiotic division results in each pair sorting it maternal and paternal homologs into daughter cells independently of every other pair. In humans each male and female gamete represents one of about 2^23 which is about 8.4 million possible chromosome combinations.

Question 87

Light reaction:

Answer 87

1st step of photosynthesis. (Photo part) Convert solar energy to chemical energy. Water is split, providing electrons and protons (H+), and giving off O2 as a byproduct. Light absorbed by chlorophyll makes the e- and H+ transfer from water to an acceptor called NADP+, where they are temporarily stored. Light rxn use solar energy to reduce NADP+ to NADPH by adding pair of e- and a H+ Generate ATP using Chemiosmosis to power addition of phosphate to ADP. (Photophosphorylation)

Question 88

Photophosphorylation:

Answer 88

Light rxn generate ATP, using chemiosmosis to power the addition of a phosphate group to ADP.

Question 89

Linear light reactions:

Answer 89

Photosystem 2 --> Photosystem 1 1. ) Light (PS 2) 2. ) Primary acceptor 3. ) H2O --> O2 4. ) Electron transport chain (Pq) PS2--> PS1 5. ) ATP 6. ) Light (PS 1) 7. ) Electron transport chain (Fd) 8. ) NADP+ reductase --> NADPH Then ATP and NADPH go to Calvin Cycle.

Question 90

Calvin Cycle Phase 1:

Answer 90

Carbon Fixation. - 3 CO2 go in Cycle 1 at a time. - Each CO2 gets attached to a RuBP. - Rubisco (enzyme) catalyzes 1st step. - Product of rxn is a 6-C intermediate (short-lived, energetically unstable) - Product splits in half, forming 2 molecules of 3-phosphoglycerate (for each CO2).

Question 91

Calvin Cycle Phase 2:

Answer 91

Reduction. - Each 3-phosphoglycerate gains additional P from ATP (1, 3-bisphosphoglycerate). - Pair of e- from NADPH reduces 1,3-bisphosphoglycerate, and also loses a P in process, becomes G3P. - For every 3 CO2 in Cycle, 6 G3P are made (only one is net gained). - One G3P exits Cycle to be used by plants, other 5 must be recycled to remake 3 RuBP.

Question 92

Calvin Cycle Phase 3:

Answer 92

Regeneration of the CO2 acceptor (RuBP). - Carbon skeletons of 5 G3P are arranged into 3 RuBP, by spending 3 more ATP. - RuBP is now ready to receive CO2 again. - Cycle continues.