Genetics 230: Chapter 2

Front 1

Mitosis and Meiosis

Back 1

Transmission of genetic material from one generation of cells to the next in eukaryotes

Front 2

Meiosis

Back 2

Leads to production of gametes

Front 3

Mitosis

Back 3

leads to production of two cells, each with same number of chromosomes as the parent cell

Front 4

Types of cells

Back 4

Prokaryotic (bacteria, archaea)
Eukaryotic (protists, plants, fungi, animals)

Front 5

Features all cells share

Back 5

- Plasma membrane
- DNA
- Ribosomes

Front 6

Composition of plant cell wall

Back 6

Cellulose

Front 7

Composition of bacterial cell wall

Back 7

Peptidoglycan

Front 8

Cell surrounded by __________ ___________.

Back 8

Plasma Membrane

Front 9

DNA is the _________ is complexed with an array of ___________ and ___________ proteins into thin fibers.

Back 9

nucleus, acidic and basic

Front 10

During ______________ phases of the cell cycle, fibers are _________ and __________ into chromatin.

Back 10

uncoiled and dispersed

Front 11

Chromatin fibers _______ and _______ to form _____________ during mitosis and meiosis.

Back 11

coil and condense, chromosomes

Front 12

Where are centrioles in the cytoplasm located?

Back 12

A specialized region called the centrosome in animal cells.

Front 13

During meiosis and mitosis, what do centrioles do?

Back 13

They organize spindle fibers for movement of centrioles.

Front 14

Chromosomes exist in homologous or heterologous pairs in diploid organisms?

Back 14

Homologous; Maternal and paternal produce one of each.

Front 15

Somatic cells

Back 15

- Body cells of given species have specific number of chromosomes
- present in homologous pair
- Humans (46 chromosomes; 23 pairs)

Front 16

Homologous chromosomes

Back 16

Carry genes for the same inherited characteristics.

- NOT identical; can carry different versions of same gene

Front 17

How many copies of genes do diploid organisms contain?

Back 17

2 copies of each gene

Front 18

Do they need to be identical?

Back 18

No

Front 19

What are the alternative forms of the same gene called?

Back 19

Alleles

Front 20

Meiosis converts the ___________ ___________ of chromosomes to the ___________ ___________.

Back 20

Diploid (2n) to Haploid (n)

Front 21

Gametes contain __________ set of chromosomes?

Back 21

Haploid

Front 22

Diploid zygote is from?

Back 22

Fusion of two gametes in fertilization.

Front 23

Sex-determining chromosomes are usually not ____________ yet behave like homologs in ___________.

Example?

Back 23

homologous, meiosis

In humans there is an X and Y chromosome.

Front 24

Cytogenetics

Back 24

The analysis of chromosomes.

E.g. maternal age of mothers increase, needed for analysis of offsprings

Front 25

Chromosomes

Back 25

Smallest to Largest; 1-21, 22 is larger than 21.

- Sex chromosomes of x and y.
- Y chromosome has least number of genes in all 22 chromosomes

- 22xx: female

- 22xy: male (recessive diseases occur more often in males because less x chromosome, compared to females- high metabolic rate)

Front 26

S phase

Back 26

DNA replication occurs and produce sister chromatids

Front 27

Sister Chromatids (a pair)

Back 27

- 2 chromatids

- Centromere (DNA that is hidden beneath the kinetochore proteins)

- Kinetochore (proteins attached to centromere)

Front 28

_____________ reproduce ____________ by binary fission.

Back 28

Prokaryotes, asexually

Front 29

Binary fission does not involve genetic contributions from _______ _____________ gametes.

Back 29

two, different

Front 30

_________ _____________ in eukaryotes requires a replication and sorting process that is more _____________ than simple binary fission.

Back 30

Cell division, complicated

Front 31

Cell cycle

Back 31

Eukaryotes that are destined to divide progress through a series of stages.

- fundamentally same among eukaryotes, conserved throughout evolution and comprised on interphase and mitosis

Front 32

G1 phase

Back 32

Check if accurate procedure is occurring.

Front 33

S phase

Back 33

Chromatids will be duplicated and undergo DNA replication and produce a pair of sister chromatids.

Front 34

Upon completion of __________, each chromosome will have a _________ chromatid, and _____ chromosomes.

Back 34

mitosis, single, and 3

Front 35

In reality, mitosis has the ___________ time duration, and is the __________ phase.

Back 35

shortest

Front 36

Interphase

Back 36

G1, S and G2

Front 37

G0 phase (Cell may remain for long periods of time)

Back 37

- cell is either postponed in making a decision to divide

- or made the decision to never divide again (being paralyzed

- terminally differentiated cells (e.g. nerve cells, cardiac muscle cells)

Front 38

Karyokinesis

Back 38

Genetic material is partitioned to daughter cells during nuclear division

Front 39

Cytokinesis

Back 39

Cytoplasmic division follows karyokinesis.

Front 40

Stages of Mitosis and are they continuous (never stops at one phase?

Back 40

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

Yes, never stops at one phase and is always continuous.

Front 41

Interphase

Back 41

- chromosomes are extended and uncoiled, forming chromatin

- longest phase of cell cycle

- genes are being transcribed and translated, cant see chromosomes clearly

Front 42

Prophase

Back 42

- chromosomes coil up and condense; centrioles divide and move apart

- chromosomes can be seen clearly

- centrioles coordinate mitotic spindle

- sister chromatids are connected at the centromere

Front 43

Prometaphase

Back 43

- chromosomes are clearly double structures, moving towards metaphase plate

- centrioles reach opposite poles; chromosomes move to equatorial plane of cell

- spindle fibers form

Front 44

Metaphase

Back 44

- centromeres align on metaphase plate (equitoral plane)

- spindle fibres bound to kinetochores associated with centromeres are responsible for chromosome movement

Front 45

Anaphase

Back 45

- centromeres split and daughter chromosomes (another words for separated sister chromatids)migrate to opposite poles

- mitotic spindle and central mirror divide holding the pair of sister chromatids together- being pulled apart

Front 46

Telophase

Back 46

- daughter chromosomes arrive at the poles; cytokinesis commences

- 3 chromatids pulled to each side, central mirror splits and each daughter chromosome has arrived at the end point pole, 2 daughter cells will arise

- Main events: cytokinesis, uncoiling of chromosomes, and re-formation of the nuclear envelope

Front 47

Mitosis produces __________ ________ with a full ____________ compliment of chromsomes.

Back 47

daughter cells, diploid

- maintains 3 pairs of chromosomes

Front 48

Significance of mitosis

Back 48

- ultimately produces 2 daughter cells having the same number of chromosomes as the mother cell

- two daughter cells are genetically identical (2N to 2N)

- maintains diploid (begins and ends with 6 chromosomes; 3 pairs)

- ensures genetic consistency from one cell to the next

- development of multicellularity relies on the repeated process of mitosis and cytokinesis, from 1 zygote to trillions of cells in the mature body of an organism

Front 49

__________ and _______________________________ are responsible for advancing a cell into the cell cycle

Back 49

Cyclins and cyclin-dependent kinases (protein enzyme that adds phosphate group to substrate)

Front 50

Checkpoints to ensure regulation in cell cycle

Back 50

G1/S, G2/M, and M (spindle assembly checkpoint)

Front 51

More than ______ cell types in mature human body, all highly __________.

Back 51

200, and regulated

Front 52

M checkpoint

Back 52

- monitored by proteins that can sense if a chromosome is not correctly attached to the spindle appartus

Front 53

G1/S and G2/M checkpoints

Back 53

- involve proteins that can sense DNA damage

- if so checkpoint proteins can prevent formation of active cyclin/Cdk (cyclin dependant kinase) complexes

- If found inaccuracy, reverse reaction will occur and discourage the drive of the cell cycle

Front 54

Checkpoint proteins

Back 54

- encoded by genes known as TUMOR SUPRESSOR GENES

e.g. P53- most important tumor suppressor gene (first line of defence) if sense something not right, will trigger DNA repair and apaptosis- program cell death.

Front 55

Check point proteins can detect __________________ such as DNA breaks and improperly segregated chromosomes.

Back 55

abnormalities

Front 56

Check point proteins check the ____________ of the genome and ___________ cells from _____________ past a certain point of cell cycle if there is ____________.

Back 56

integrity, prevents, progressing, damage

Front 57

Thus, checkpoint proteins prevent __________/____________ ________ from surviving and ____________ that otherwise may lead to uncontrolled cell _____________ and cancer.

Back 57

mutations/mutant cells, dividing, proliferation