Genetics

K W L

• What makes you…you?

• How do you get your DNA?

• Your DNA!

• Heredity: the passing of physical characteristics from parents to offspring

• Genetics: study of heredity

• Deoxyribonucleic Acid

• It is in the shape of a Double helix = twisted ladder

• DNA stands for…

• DNA is your genetic code

• 4 nitrogen bases make up your “genetic alphabet”. – A = adenine– T = thymine– G = guanine– C = cytosine

• These bases can be arranged differently like the letters of the alphabet to make different words. Your genetic words tell your body what protein it needs to make to get a certain job done.

• Remember:• A pairs with T• G pairs with C

Complete the dna strand…

• AAG GCC ATA GAC

• A change in the pattern creates a mutation. This may be good, bad or neutral (no effect) for the person.

• Chromatin vs. Chromosomes

• Chromatin: unwound DNA (cell is not dividing)

• Chromosome: Scrunched up DNA (cell is dividing)

Both

are

DNA!

• You have 23 pairs of homologous (same size, shape and genetic info) chromosomes (23 from your mom and 23 from your dad). That’s 46 total!

• Each pair of chromosomes has genes for certain traits on it.

• The sex chromosomes are x and y

• xx for a girl and xy for a boy.

• This means dad determines the baby’s gender!

• A karyotype lets you see all of the chromosomes a person has!

Cell Cycle Interphase = normal cell activity

G1,S,G2

Mitosis = cell division

PMAT = Prophase Metaphase Anaphase Telophase

Cytokinesis = cell splitting

• Mitosis • 1 cell divides to create 2 identical cells!

Create a mitosis flip book, write the name of the phase and

draw what it looks like

(we will only use the right hand side of the book for mitosis….we will use the left hand side later for meiosis)

Front Cover….

Mitosis:

Cell Division

2 identical cells created

2nd page

Prophase: DNA scrunches into chromosomes

3rd page

Metaphase: Chromosomes line up in the middle of the cell

4th page

Anaphase: Chromatids (2 halves of the chromosome) are separated and move to

opposite sides of the cell

5th page

Telophase: cell begins to divide into two

6th page

Cytokinesis: 2 identical cells are formed

• Meiosis • The chromosome pairs separate and are divided into two different cells. This creates gametes (sperm and egg cells) that have only half as many chromosomes as the regular body cells.

• Body cell = 46 total chromosomes (diploid)

• gametes = 23 total chromosomes (haploid)

Why bother splitting the numberOf chromosomes in half?

• Meiosis 1: – Prophase 1 = DNA scrunches into

chromosomes– Metaphase 1 = chromosomes line

up in the middle across from their pair

– Anaphase 1 = the pairs of chromosomes separate to opposite ends

– Telophase 1 = the two cells split

• Meiosis 2:– Metaphase 2 =

chromosomes line up in the middle in a straight line

– Anaphase 2 = the chromosome splits sending one copy one way and the other copy the other way

– Telophase 2 = the cells separate and you know have 4 haploid gametes!

Create a meiosis flip book, write the name of the phase and

draw what it looks like(use the left hand side of the flip book you created for mitosis!)

Front Cover….

Meiosis:

Creates gametes

(1/2 # of chromosomes)

2nd page

Meiosis 1:

One body cell divides into 2

3rd page

Prophase 1: DNA scrunches into chromosomes

4th page

–Metaphase 1 = chromosomes line up in the middle

across from their pair

5th page

– Anaphase 1 = the pairs of chromosomes separate to opposite ends

6th page

Telophase 1 = the two cells split

7th page

Meiosis 2:

Two haploid cells divides into 4 gametes

8th page

Metaphase 2 = chromosomes line up in the middle in a straight line

9th page

Anaphase 2 = the chromosome splits sending one copy one way and the other

copy the other way

10th page

– Telophase 2 = the cells separate and you know have 4 haploid gametes!