Genetics Unit

Cell Cycle/Mitosis

Mitosis is a part of the cell cycle when replicated chromosomes are separated into two new nuclei. Cell division gives rise to genetically identical cells in which the number of chromosomes is maintained.

Interphase

G1 - primary growth phase

S - replication of chromatin

G2 - organelles replicated

1.Prophase

In this stage Centrioles move to opposite poles of the cell, then Chromatins condense into chromosomes and duplicated chromosomes become visible. Sister chromatids also are joined at the centromere. then the nuclear membrane breaks down. lastly Spindle fibers begin to extend from the centrioles

2.Metaphase

firstly Duplicated chromosomes line up along the equator of the cell. Then Spindle fibers attach at the centromere of each duplicated chromosome. Then the Duplicated chromosome is held perpendicular to the spindle fibres. lastly Chromosomes are still condensed and thick

3.Anaphase

In this stage chromatids separate at the centromere
to produce two identical chromosomes. Then Each chromatid is pulled toward opposite poles as spindle fibres shorten

4.Telophase

In this stage the nucleolus reappears, spindle fibers dissapear, cytoplasm pinches inward at the equator
creating a furrow, chromatids uncoil and elongate, and there will be 2 nuclei in 1 cell temporarily.

5.Cytokinesis

In this stage the cytoplasm and organelles are distributed
between two daughter cells.

Meiosis

Meiosis, the process by which sexually reproducing organisms generate gametes, is an essential precondition for the normal formation of the embryo

Interphase

G1 - primary growth phase

S - replication of chromatin

G2 - organelles replicated

Meiosis I

Prophase I

In this stage Chromatin condenses into chromosomes, centrioles move to opposite poles, spindle fibers form from centrioles, and the nuclear membrane breaks down

Metaphase I

In this stage the tetrads line up along the equator randomly this is so genetic variation can occur, then the spindle fibers attach to the pair of sister chromatids

Anaphase I

In this stage the chromosome pairs are
separated and are pulled to opposite ends

Telophase I

In this stage the nuclear membrane reforms and the
spindle fibers retract.

Cytokinesis I

Cytokinesis occurs forming two genetically different daughter cells

Meiosis II

Prophase II

In this stage the nuclearmembrane begins to break down, spindle fibers begin to form, and the centrioles begin to move to poles

Metaphase II

In this stage the chromosome pairs align along the equator of the cell, and then the Spindle fibers attach to centromeres of the chromatids

Anaphase II

In this stage the spindle fibers pull
the chromatids apart

Telophase II

In this stage the Nuclear membrane reassembles, chromosomes decondense, and the spindles disappear

Cytokinesis II

Four genetically different daughter cells form

Mistakes in Meiosis

1) Errors During Chromosome Division

this error occurs when chromosomes in meiosis do not
divide properly, which results in gametes with extra or missing chromosomes

Monosomy - One missing chromosome

Results in Turner’s Syndrome

Trisomy - One extra chromosome

Results in Klinefelter Syndrome

Polysomy - more than 1 extra chromosome

Results in Down Syndrome

2) Errors During Crossing Over

This Occurs when DNA is not exchanged
properly during recombination

Duplication

Results in an extra
copy of the gene

Deletion

Results in a loss of
genetic information

Inversion

Translocation

Results in a Gene not being able to be
expressed properly

Sex Linked Traits

Humans - XX is female and XY is male

Autosomal trait

In this trait the gene is carried on a non sex chromosome. which in presented in two copies in both sexes.

Sex-linked trait

In this trait genes are carried on one of the sex chromosome that is in both sexes.

Y-linked trait

this trait is in humans, which talks about a gene that is carried on the Y chromosome

Carrier

A female who “carries” the recessive allele on one X chromosome

Blood Basics

What Makes up our blood?

Red blood cells

This cell is the most abundant cells in our blood. They are produced in the bone marrow and have a protein called hemoglobin that carries oxygen to our cells.

White blood cells

Are part of the immune system and help protract us from infections and diseases.

Plasma

This part of the blood contains electrolytes, nutrients and vitamins, hormones, clotting factors, and proteins such as antibodie.

PLATELETS

these are tiny blood cells that help your body form clots to stop bleeding.

Type A (AA,AO)

Plasma Antibodies = b

A+

1 in 3 people have it

A-

1 in 16 people have it

Type B (BB,BO)

Plasma Antibodies = a

B+

1 in 12 people have it

B-

1 in 67 people have it

Type AB (AB)

Plasma Antibodies = NONE

AB+

1 in 29 people have it

AB-

1 in 167 people have it

Type (OO)

Plasma Antibodies = ab

O+

1 in 3 people have it

O-

1 in 15 people have it