Karyotypes

What are they? A “picture” of a person’s 46 chromosomes.

Chromosomes are arranged in homologous pairs. Chromosomes are arranged in homologous pairs. Homologous pairs – chromosomes of the same size and shape, but are not genetically idenitcal. Homologous pairs – chromosomes of the same size and shape, but are not genetically idenitcal.

Why use karyotypes? To determine sex: To determine sex: Male- XY Male- XY Female- XX Female- XX To see abnormalities in chromosomes To see abnormalities in chromosomes Extra chromosomes Extra chromosomes Missing chromosomes Missing chromosomes Extra/missing pieces of chromosomes Extra/missing pieces of chromosomes

Normal Karyotype

What’s the problem?

Turner Syndrome 45, X0 – 45 chromosomes, only 1 X chromosome 45, X0 – 45 chromosomes, only 1 X chromosome Sex: female Sex: female Symptoms: Symptoms: –Short stature –swelling of the hands and feet –Low hairline –Low-set ears –Reproductive sterility

What’s the problem?

Klinefelter's syndrome 47, XXY 47, XXY Sex: Male Sex: Male Symptoms: Symptoms: –Sterility –Youthful build –“round body”

What’s the problem?

Down Syndrome Trisomy 21 (three copies of chromosome #21) Trisomy 21 (three copies of chromosome #21) Symptoms: Symptoms: –head may be smaller than normal & abnormally shaped. –a flattened nose –protruding tongue –upward slanting eyes –short hands and fingers

What’s the problem?

Edward’s Syndrome Trisomy 18 Trisomy 18 Symptoms: Symptoms: –Failure to grow –Low set, malformed ears –Abnormalities in the bones of the hands and feet –Kidney and heart defects

Interphase Cell duplicates DNA Cell duplicates DNA Individual chromosomes not yet visible. Individual chromosomes not yet visible.

CANCER What is it? Uncontrolled cell division of abnormal cells which may result in death. Metastasis: Cells from malignant tumors may break off and travel to other parts of the body, forming new tumors.

The Four phases of Mitosis PMAT

Prophase chromatin condenses (chromosomes are now visible) Chromosomes consist of two sister chromatids nuclear membrane disappears Centrosomes start to move to opposite ends (poles) of cell spindles begin to form

Metaphase Spindles are fully formed chromosomes are attached to spindles at the centromeres Chromosomes line up at the center (equator) of the cell

Anaphase Sister chromatids separate and move to opposite poles. Each chromatid is now considered an individual chromosome

Telophase 2 nuclear envelopes reform Chromosomes uncoil into chromatin Spindles disappear

Cytokensis cytoplasm is divided in half  ANIMAL PLANT 

Animation of Mitosis