Reproduction Revision Notes

How to calculate total magnification of a light microscope:
The total magnification is calculated by multiplying the magnification of the objective lens by the magnification of the eyepiece (ocular lens).
$\text{Total Magnification} = \text{Objective Lens Magnification} \times \text{Eyepiece Magnification}$

List the 7 characteristics of life: While different sources may vary slightly, a common list includes:
1. Organization: Living things exhibit a complex organization, from cells to tissues to organs to systems.
2. Reproduction: Living things reproduce to create more of their own kind, either sexually or asexually.
3. Growth and Development: Living things grow and develop, increasing in size and complexity.
4. Response to Stimuli: Living things respond to stimuli in their environment.
5. Homeostasis: Living things maintain a stable internal environment.
6. Energy Processing: Living things obtain and use energy to power their life processes.
7. Adaptation: Living things adapt and evolve over time.

Draw and label a typical animal cell observed under X100 magnification. A typical animal cell includes:
- Cell membrane
- Cytoplasm
- Nucleus
- Mitochondria
- Ribosomes
- Endoplasmic reticulum (ER)
- Golgi apparatus
- Lysosomes

How does asexual reproduction differ from sexual reproduction?
- Asexual Reproduction: Involves one parent and produces offspring that are genetically identical to the parent (clones). Examples include budding, binary fission, and vegetative propagation.
- Sexual Reproduction: Involves two parents and produces offspring that are genetically unique, with a combination of genes from both parents. Involves the fusion of gametes (sperm and egg).

For each of the following methods of asexual reproduction, name one organism that reproduces in this manner:
- Budding: Yeast, Hydra.
- Spore Formation: Fungi (e.g., molds, mushrooms), ferns.
- Binary Fission: Bacteria, amoeba.
- Vegetative Reproduction: Plants (e.g., strawberries, potatoes).

Name the 2 different types of gametes produced by humans:
- Sperm cells (produced by males)
- Egg cells (produced by females)

Gametes have a haploid chromosome number. What is this haploid number in humans?
- The haploid number in humans is 23 ( $n = 23$ ). This means that gametes (sperm and egg cells) contain 23 chromosomes each.
How many chromosomes are there in a human body cell?
- Human body cells (somatic cells) are diploid, meaning they have two sets of chromosomes. The diploid number in humans is 46 ( $2n = 46$ ).

Where are egg cells produced in a human female?
- Egg cells (ova) are produced in the ovaries.
What does the term ovulation describe?
- Ovulation describes the release of a mature egg cell from the ovary.
Through what structure does the egg travel to reach the uterus?
- The egg travels through the fallopian tube (also known as the oviduct) to reach the uterus.
Where does fertilization usually take place?
- Fertilization usually takes place in the fallopian tube.
What happens at the end of the menstrual cycle if fertilization has not taken place?
- If fertilization has not taken place, the uterine lining (endometrium) is shed, resulting in menstruation.

Where are sperm cells produced in a human male?
- Sperm cells are produced in the testes (specifically, in the seminiferous tubules).
What is the purpose of the testes being found outside the human body in the scrotum?
- The scrotum provides a cooler environment for the testes, which is necessary for optimal sperm production. Sperm production is most efficient at a temperature slightly lower than the normal body temperature of $37^{\circ}C$ .
In terms of reproduction, what is the function of the vas deferens?
- The vas deferens transports sperm from the epididymis (where sperm are stored) to the ejaculatory ducts, which then lead to the urethra.

List 4 secondary sexual characteristics in males.
- Growth of facial and body hair
- Deepening of the voice
- Increased muscle mass
- Adam's apple development
List 4 secondary sexual characteristics in females.
- Breast development
- Widening of the hips
- Menstruation
- Development of subcutaneous fat

What is the function of the placenta?
- The placenta provides oxygen and nutrients to the developing fetus and removes waste products from the fetal blood. It also produces hormones necessary for maintaining the pregnancy.
Explain why it is dangerous for a pregnant woman to drink alcohol during her pregnancy.
- Alcohol can cross the placenta and enter the fetal bloodstream. Because the fetus's liver is not fully developed, it cannot process alcohol efficiently. This can lead to fetal alcohol spectrum disorders (FASDs), which can cause a range of physical, behavioral, and cognitive problems in the child. There is no known safe amount of alcohol consumption during pregnancy.