CH 12 Meiosis: Binary, Vocab, Cell Cycle

Define cell divison

When one pair of cells divides into two daughter cells

(not as simple as seems(

What are the requirement for cell divison

1. After divison, the 2 daughter cells have the full genetic info of each parent cell

2. Parent cell is big enough to give enough cytoplasm in 2 daughter cells

Cell divison for prokaryotes

Binary fisson

Cell divison for eukaryotes

cytokensis and mitosis

Brief overview of events for cell divison

1. Copying the DNA

2. DNA seperated (untwisited)

3. Cytoplasm divided to make 2 daughter cells

How is DNA replicated

2 DNA strands are made up of complementary bases

during replications they are untwisted

and a new DNA strand is created (based on those individual strands) and twisted with it

(following the nitrogenous base sequence of other strands ATCG, purine/pyrimidine

What do Prokaryotes and Eukaryotes differ in cell divison

because they have different structures

How do prokaryotes and eukaryotes differ relating to their genetic material

Prokaryotes DNA molecule is looped in a full circle

While eukaryotes DNA is condensed into lines of chromosomes

&

Prokaryotes lack a nucleus

Eukarotes have a nucleus

Overview binary fision

during this process a prokaryote cell

1. creates a copy of its DNA (replicates)

2. gets bigger in size (enlarges)

3. Spilts into 2 “daughters” (divides))

each daughter cell should have one copy of each parents’ replicated DNA

explain how cell divides during binary fissson

when a prokaryote spilts

they use a form a ring of Ftsz proteins called ParM protein

the ring closes in, spilting the prokaryote

Unreplicated chromosome

DNA (double stranded helix of polynucleotides)

that is wrapped around histone protein

when these proteins are loosely packed together it makes chromatin (loops)

when this chromatin (loop) condensed → Chromosome (linear)

nucleosome

the core of histones protein that has DNA helix wrapped around it

How many chromosomes in Humans

23

Recap of DNA’s function, genes function (blueprint/coding)

DNA acts as a blueprint for the cells genetic material

these genes that make up DNA are used as a blueprint to make specific RNA

RNA a copy of the blueprint, has instructions used to made specific proteins

this is how DNA, Genes codes for a specific protein

Chromatid

one half of a duplicated chromosome (single chromosome)

is attached along their length by proteins called cohesins

before dividing the cell makes two copies (sister chromatids) which join together (at centromere) to make 1 duplicated chromosome. alone it is 1 chromosome because chromosomes are counted by # of centromeres

SIster chromatids

two single identical chromosomes attached together at centromere

they are identical because one chromosome was replicated

cohesins

forms rings (with proteins) that hold the sister choromatids together

Condensins

proteins that forms rings which condense the chromosome

Centromere

piece that connects the chromosome together once mitosis begins

Nuclear lamins

insulation on the inner nuclear envelope (intermidtate filaments)

they keep the DNA in place, but disentegrate during mitosis

Replicated chromosome

a chromosome made of 2 sister chromatids

they have two copies of the same DNA helix

Kinetochore proteins

proteins on the centromere which act as a binding site for microtubules.

Microtubules

connect to kinetochore proteins on centromere and moves the chromosomes to the pose

Pose

the posistion in which sister chromatids seperate

Spindle Apparatus

made of microtubules which come out of centrosomes

that use a mechanical force to align replicated chromosomes in early mitosis

and pull them apart in late mitosis

(movement caused by microtubules ability to assemble, diassemble, + - ends)

microtubule organizing centres (MTOCs), animal, plant

microtubules which come out of centrosomes

moves chromosomes

in animal cells they are centrosomes with a pair of centrioles (2 centrosomes facing 90 degrees so they can project microtubules all sides)

in plant cells they are NEDD1 complexes

centrosome vs centromere

centrosomes are in the cytoplasm around the centromere, they form

the centromere is the center of chromatids, chromosomes holding them together, and the attachment site for micotubules

Different types of microtubules

the plus end of microtubules can form 3 different types of microtubules

Polar microtubule

Astral microtubule

Kinetochore microtubule

polar microtubules

microtubules which grow from spindle pole (side) and overlap with eachother

minus end facing centrosome, plus end facing outward chromosome.

it rainbows a litte over halfway and meets other microtubule. polar because opposite sided microtubules go to to other side

responsible for pulling force

Poles

the spindle poles are where the plus ends of microtubules grow out of.

one on each side of cell

Astral microtubule

smaller microtubles that anchors the MTOC (ex. centrosome) in the plasma membrane

plus side facing membrane, minus facing centrosome

Kinetochore microtubules

microtubule which connects the centrosome to the kinetochore (binding site at chromosome’s centromere)

Kinetochore structure how it connects with microtubule (and generates pulling force)

kinetochore fibres form a ring around the microtubule

kinetochore plates are the binding sites where the ringed microtubule is attached to centromere

microtubule can move the chromosome by depolymerizing the end (breaking them down into smaller molecules) shrinking this end creates a pulling force

What are the 2 distinct stages of the cell cylce for (euk)

M phase

Interphase

The M phase

the time during which the parent cell divides into 2 identical daughter cells

Interphase

the time in between 2 Mphases where the cell grows and prepares to spilt

this stage takes the most time

the chromosomes are uncoiled (chromatin) at this point

this stage has 3 phases

3 stages of interphase

G1 (gap 1)

S (synthesis

G2 (gap 2)

G1

first part of interphase

the cells grows, increases in protein

proteins that regulate the cell are activated (to start pathways for S)

S phase

2nd part of interphase

where DNA is replicated (synthesis of DNA)

G2

the 2nd gap phase (last part of interphase)

cell prepares to spilt (cytokenisis and mitosis)

M plhase

spilting of the cell has 2 parts

1. Mitosis

2. Cytokinesis

Mitosis

when the replicated chromosomes spilt into their own cells

Cytokinesis

when the cytoplasm is divided between spilting cells