Cell Reproduction: Chromosomes, Genes, and Proteins

• Reproduction is a characteristic of life.
• The objectives are to familiarize yourself with genetic terms and compare asexual and sexual reproduction.

Chromosomes, Genes, and Proteins

• Each cell's nucleus contains DNA, which is the genetic code of life.
• During cell division, DNA becomes visible under a microscope as an X-shaped structure called a chromosome.
• A chromosome is essentially coiled up DNA.
• A gene is a segment of DNA that codes for a specific protein.
• A human has 46 chromosomes arranged in 23 pairs
• A potato has 48 chromosomes.
• DNA is the genetic code inside the nucleus of cells.
• Each gene codes for proteins which in turn are used to make characteristics.
• DNA gets passed from one generation to the next via reproduction.

Types of Reproduction

• Asexual and sexual reproduction are the two types of reproduction.

Asexual Reproduction

• Asexual reproduction requires only one parent.
• The offspring are genetically identical to the parent.
• Binary fission, such as in bacteria, is an example of asexual reproduction.
• Spores, seen in fungi, are tiny reproductive structures containing a nucleus and cytoplasm with a protective covering.
• Plants have many forms of asexual reproduction.
• Runners are aboveground stems. New plants grow at the end of the runner, such as strawberries and spider plants.
• Root stores are thickened underground stems that can grow into a genetically identical plant, examples include tubers (potatoes), rhizomes (ginger) or Bulbs (tulips).
• Disadvantages to asexual reproduction include the preservation of both good and bad genes, leading to less adaptability in new environments.
• Asexual reproduction can cause overcrowding in plants.
• Advantages to asexual reproduction is that it only requires one parent, and it is important in food production because offspring are identical.
• Asexual reproduction doesn't require organisms to wait to mature in order to produce gametes or sex cells.

Sexual Reproduction

• Sexual reproduction differs from asexual reproduction; asexual reproduction requires only one parent, with the offspring being genetically identical.
• Sexual reproduction requires two parents.
• The offspring are genetically different from both parents.
• Humans have special cells called gametes.
• Gametes are sex cells used in forming an offspring.
• Gametes only have 23 chromosomes.
• Sperm has 23 chromosomes.
• An egg has 23 chromosomes.
• When combined, 23 + 23 = 46 chromosomes in the offspring.