Biology Unit 4 Notes: Reproduction & Karyotyping

BIOLOGY

Unit 4 Notes:Reproduction & Karyotyping

(1) Types of Reproduction

SEXUAL ASEXUAL• Requires 2 parent organisms. • Requires 1 parent organism.

• Sperm + Egg fertilize one another to form a Zygote.

• The single organism makes a copy of itself and divides.

• The offspring are genetically unique from the parents, but contain a random combination of parental genes.

• The offspring are genetically identical to the parent.

• Used by humans, other animals and plants.

• Used by yeast, sponges, and bacteria.

• Pros Produces genetically different babies, increasing the survival rate of the population.

• Cons Requires a lot of time and effort.

• Pros Extremely efficient.• Cons If the parent has genetic

defects / deficiencies, all of its offspring will also be “weak”.

(2) Types of Asexual Reproduction:

• Binary Fission:The organism makes an identical copy of itself, divides and splits in two.

• Budding:The parent organism develops a small bud off its side, which develops into an exact copy.

(3) Bacteria & Conjugation• Bacterial Conjugation:

The process by which bacteria exchange extra DNA structures (called plasmids) which can increase resistance to antibiotics.

• When Does This Happen In Us?– If you don’t finish a full round of antibiotics…– This allows a mix of weaker bacteria to survive, along with

the more fit ones (with the plasmids).– Bacteria can then pass on their extra special DNA.– This makes more bacteria resistant to your medicine.

• What is the Long Term Concern?– Some wonder if our overuse of antibacterial body products

and antibiotic medicines could be promoting the evolution of antibiotic-resistant bacteria.

• Purpose:To look at chromosome pairs to identify chromosomal-disorders.

• Process:1. Stain DNA.2. Organize longest shortest.3. Organize by banding pattern. 4. Sex chromosomes at the end.5. Look for too many, missing, shortened, or

lengthened chromosomes.

(4) Karyotyping:

• Sex Chromosomes:– Male = X and Y– Female = X and X

• “Normal” Numbers:– 23 pairs OR 46 total

(5) Chromosomes:

• Chromosomes:– Trisomy 21 = 3 chromosomes at #21– Total = 47 chromosomes

• Physical Characteristics:– Round-Asian-Like Facial features, short

stature, heart defects– Shorter lifespan– Prone to Alzheimer’s and leukemia

(6) Down Syndrome:


• Physical Characteristics:– Eye, Brain and Circulatory defects– Cleft Palate– Death typical w/in months of birth

(7) Patau Syndrome:


• Physical Characteristics:– Every organ defected– Death w/in months after birth

(8) Edward’s Syndrome:

• Chromosomes:– XXY – Total = 47 chromosomes

• Physical Characteristics:– Male sex organs, but underdeveloped + sterile– Other feminine body characteristics– Normal intelligence

(9) Klinefelter Syndrome:

• Chromosomes:– Only 1 X chromosome– Total = 45 chromosomes

• Physical Characteristics:– Female– Do not mature sexually + are sterile– Short stature– Normal Intelligence– (Most die before birth)

(10) Turner’s Syndrome:

Biology Unit 4 Notes: Reproduction & Karyotyping

Education