Human Anatomy and Physiology Lab

Genetic Inheritance

Anatomical Terminology and Orientation Review

Always refer to anatomical position with directions!!

Planes

• Removes the top of the head?

• Divides the toes from the body?

Body landmarks

PatellerBrachial

Human Anatomy and Physiology Lab

Genetic Inheritance

DNA

Inherited genetic material inside each cell

Composed of nucleotides

3 parts to a nucleotide: 1. Nitrogenous base

-A – T-G -- C

2. Pentose sugar 3. Phosphate group - “backbone”

DNA in the Cell

Located within the cell’s nucleus

Remains loosely coiled in nondividing cells but forms into chromosome before dividing

Passing on DNA

• Cells divide to pass on genetic material• Somatic (body) cells undergo mitosis and

cytokinesis– Replaces dead or injured cells– Adds new cells during growth

• Germ cells (sperm or oocytes) undergo meiosis– Produces gametes

The Cell Cycle

Mitosis: Cell duplicates its contents and divides in two

3 Main Stages Interphase Mitosis Cytokinesis

Interphase• DNA replicated• Cell does most of its growing

• 3 Phases:G1 - replication of most organelles and cytosolic components

S – DNA replication

G2 – enzymes and other proteins are synthesized in prep for division

Mitotic Phase• Prophase

– DNA shortens into chromosomes– Each centrosome moves to an opposite pole of cell– Nucleolus disappears, nuclear envelope dissolves– Spindle fibers and asters become visible

Mitotic Phase• Metaphase

– Centromeres of chromatid pairs are aligned at exact center

• Anaphase– Centromeres split, indentical

sets of chromosomes moved to opposite poles

Mitotic Phase

• Telophase– Chromosomes uncoil and revert to chromatin form– Nuclear envelope forms around each mass

Cytokinesis

• Division of the cytoplasm

• NOT A PART OF MITOSIS!!• Mitosis is a nuclear event, cytokinesis is cytoplasmic

Karyotype

Alleles

Genotype Phenotype

• AA, Ab

• aa

Punnett Squares

• Heterozygous female with freckles x heterozygous male with freckles

F f

F FF Ff

f Ff ff

1 : 2 : 1

Codominance

Incomplete Dominance

Neither trait is dominant

Heterozygotes show a blending of the traits

X – linked traits

• Traits passed on by the sex chromosomes

X – Linked Punnett Squares

XH Xh

XH XH XH XH Xh

Y XH Y Xh Y

Epistasis

Action or expression of a gene influences that of another

Next Week

• Quiz first 15-20 minutes of class. Do not be late!!!

• Covers material from Labs 1 & 2 and definitions from Lab 3.

What is due today?

• Integrate: Heredity: Principles of Inheritance– Objectives on page 31

• Skip questions on “sex-influenced” and “holandric” (questions # 10 & 14)

– Read and answer Activity Questions on pages 33- 40, 42, and 45-46 (only do section V)

– General questions # 1 - 3