BIOL2030 - Mitosis, Meiosis, Cell Cycle review

Label the five steps of mitosis as well as interphase

A. Metaphase

B. Prophase

C. Anaphase

D. Telophase

E. Prometaphase

F. Interphase

what is PP-MAT?

Prophase, Prometaphase, Metaphase, Anaphase, Telophase of the Mitotic cycle

Number of chromosomes in the cell cycle?

G1: 4

S: 4

G2: 4

PP: 4

M: 4

A: 8

T & Cytokinesis: 4

Number of DNA molecules per cell in the cell cycle?

G1: 4

S: 4 --> 8

G2: 8

PP: 8

M: 8

A: 8

T & Cytokinesis: 4

How many chromosomes in the G1 phase?

2n = 4 chromosomes

- diploid chromosome number which means cell contains 2 complete sets of chromosomes.

(T/F) these are the steps in Meiosis to produce two genetically unique haploid gametes from a single diploid cell?

True

what is DNA (deoxyribonucleic acid)

The hereditary material in humans and almost all living organisms. It stores genetic information in the sequence of nucleotides, which directs protein production and influences an organism's phenotype. DNA is copied and passed on to offspring, while the phenotype itself is not inherited.

what are genes?

they are units of hereditary information and a chromosomal region that codes for a functional transcript.

what is an allele?

one of the different forms of a gene that exists at a single locus

What is a chromosome?

A large, threadlike structure made of DNA and proteins, visible during mitosis. It carries many genes essential for cellular functions and ensures genetic information is accurately passed to daughter cells.

Chromatin

a complex of DNA and protein found in eukaryotic cells

Eukaryotic chromosomes

linear molecule of DNA associated with histone proteins and packaged into higher-order structures

Telomere

stabile ends of linear chromosmes

Centromere

constricted region of chromosomes where the kinetochore forms and spindle microtubules attach during cell division.

Where are sister chromatids held together?

centromere

locus (loci - plural)

position of gene on a chromosome, or particular location on a chromosome

what are the different morophologies of eukaryotic chromosomes?

Metacentric: centromere in middle

submetacentric: centromere slightly off center

acrocentric: centromere close to end

telocentric: centromere beside telomere

Haploid

N, one copy of genetic material subdivided into chromosomes

Diploid

2N, two copies of genetic material subdivided into chromosomes creating a homologous pair

Autosomes

chromosomes that are the same for both sexes

Sex chromosomes

a pair of chromosomes that differ between males and females

Eukaryotic cell reproduction

dealing with multiple linear chromosomes

Eukaryotic cell division

1. copy each chromosome

2. separate DNA into each daughter cell

a) accommodate nuclear envelope

b) ensure exactly one copy of each linear DNA strand ends up in each daughter cell

1 centromere =

1 chromosome

Prior to S-phase

1 linear strand of DNA

After S-phase:

2 linear strands of DNA

Are chromosomes maximally condensed?

no, chromosomes become maximally condensed only during mitosis

Is the cytoplasm often reduced during mitosis?

yes, by about 1/2

How many sets does each daughter cell get in mitosis?

each daughter gets exactly 2 haploid sets of chromosomes

Meiosis

the production of haploid (n) gametes

Fertilization

the restoration of diploid state (2n) in the next generation

How are diploid organisms produced?

By fusion of 2 haploid gametes

Gametogenesis (Meiosis)

production of gametes [ Ovum (n) and spermatozoa (n) ] to be fertilized

cell division after fertilization (Mitosis)

zygote (2n) produces organisms (2n)

What does sexual reproduction do?

maintains the correct diploid state across generations

meiotic cell "cycle"

-Interphase (G1, S, G2)

-Meiosis I - separation of homologous chromosomes (2N-->N)

- interkinesis

-Meiosis II - separation of sister chromatids

- 4 haploid cells

What are the 5 substages of prophase I?

- pairing of homologous chromosomes

- synapsis

- tetrad (bivalent) structures

- crossing over

- visible chiasmata

Meiosis yields

4 sets of haploid gametes, these haploid cells are genetically different from one another and are different from the parent

independant assortment (genetic variation 1)

independent segregation of genes during the formation of gametes from paternal and maternal chromosomes

crossing over (genetic variation 2)

the physical exchange of genetic material among non-sister chromatids