SC235Unit EightAngela M. Foster, EdD

AFoster3@kaplan.edu

AIM: AFoster3

Image credits: Microsoft Clip Art

Mitosis

Cell division plays a role in-The replacement of lost or damaged cells.-Cell reproduction and growth.

Before a parent cell divides, it duplicates its chromosomes.

The two resulting “daughter” cells are genetically identical.

Some multicellular organisms can divide into pieces that then grow into new

individuals.

Figure 8.2b

Figure 8.2c

Chromosomes

-Chromosomes-Are made of chromatin, a combination of DNA and protein molecules.-Are not visible in a cell until cell division occurs.

Figure 8.4

The Cell Cycle

Figure 8.8.1

Meiosis

Sexual reproduction is different.

-It requires fertilization of an egg by a sperm.

-Production of egg and sperm is called meiosis.

Meiosis-In meiosis,

-Haploid daughter cells are produced in diploid organisms.-Two consecutive divisions occur, meiosis I and meiosis II, preceded by interphase.

-Crossing over occurs.

-Sexual reproduction depends on-Meiosis.-Fertilization.

Human Chromosomes

-A somatic cell (any cell that is NOT sperm or egg)

-Is a typical human body cell.

-Has 46 chromosomes.

Human Reproduction-Humans are diploid organisms.

-Their cells contain two sets of chromosomes.-Their gametes are haploid, having only one set of chromosomes.

- Fertilization-Is the fusion of sperm and egg.-Creates a zygote, or fertilized egg.

Meiosis Overview

Origins of Genetic Variation

• Offspring of sexual reproduction are genetically different from their parents and from one another.

• In independent assortment, every chromosome pair orients independently of the others during meiosis.

• The human egg cell is fertilized randomly by one sperm, leading to genetic variety in the zygote.

• In crossing over,-Homologous chromosomes exchange genetic information.-Genetic recombination occurs.

Unit Eight – Lab Project 5 – Part 1Pedigree Analysis

Once completed, save the pedigree as a pdf. Click the “save printable family history’ button to save a pdf file.

Lab Assignment Question 1: On your pedigree, the shaded squares and circles indicate people who are/were affected by the disease you selected. From looking at your pedigree chart, does it appear to you that this disease or trait is inherited? Explain your thinking.

For this week's lab, be sure to hand in both the pedigree chart you have saved to your computer AND your response to the question above.

Unit Eight – Discussion

• Choose a genetic disorder to review

-Make sure it is GENETIC

-Make sure it has NOT already been reviewed by a classmate

Questions??

Image credits: Microsoft Clip Art