Notes, abstracts, papers, exams and problems of Biology

The purpose of sexual reproduction is to produce offspring through the fusion of female and male gametes from two individuals (fertilisation).

Asexual reproduction, where a plant can reproduce without involving another plant, is possible in hermaphrodites, which have both male and female organs.

Pollination: Pollen grains travel from the flower to the other plant by wind or by animals.

Fertilisation: When a pollen grain reaches the stigma, the male gamete joins with the female gamete.

Seed Formation: The zygote develops and then grows into a new plant.

Fruit Formation:

Tissues

Types of Tissues

• Epithelial Tissue: Covers the interior and exterior body surfaces.
• Connective Tissue: The most abundant type of tissue.
• Nervous Tissue: Transmits nerve impulses.
• Muscle Tissue: Provides movement.

Homeostasis

Homeostasis is the maintenance of a constant internal environment within an organism. One mechanism to achieve homeostasis is feedback inhibition, where a stimulus produces a response that opposes the original stimulus.

Nutrition

Macronutrients

• Carbohydrates: The major source of energy in the body.
• Fats: A combination of glycerol and fatty acids. They absorb fat-soluble vitamins, store energy, and protect body organs.
• Proteins: Molecules that supply raw materials for growth and repair.

Micronutrients

• Vitamins: Organic molecules

Head and Neck Anatomy: Quick Facts

1. Which muscle does the superficial cervical fascia contain? Platysma
2. Which part of the mandible is the stylomandibular ligament inserted? Angle and posterior border of ramus
3. What kind of secretion does the sublingual gland produce? Mixed, mainly mucous
4. What are the two anastomoses of the deep branch of the submental artery? Infra labial (facial) & mental artery (inferior alveolar)
5. Which nerve runs through the sphenopalatine foramen? Nasopalatine nerve
6. In which part of the brain is the hippocampus located? Limbic system
7. Which masticatory muscles do muscular branches of the facial artery supply? Medial pterygoid & masseter
8. What four cranial nerves (CNs) are related to the parasympathetic system? 3, 7, 9, 10
9. What

Respiratory System

Fetus: developing unborn baby.

Organelles and Functions:

• Rough Endoplasmic Reticulum: Responsible for the assembly of many proteins • Cell Membrane: Controls the movements in & out of the cell and organelles • Golgi Apparatus: Process and bundle macromolecules like proteins and lipids • Mitochondria: Perform cellular respiration 0 Breaks nutrients into energy • Nucleus: Contains a majority of the genetic material • Nucleolus: Rewrite ribosomal RNA and combine it with proteins • Smooth Endoplasmic Reticulum: Makes cellular products like hormones and lipids • Lysosome: Digestion and waste removal • Flagella: Allows cells to move • Vesicle: Transport vesicles move molecules within the cell • Ribosomes: Makes proteins within cells • Cytoskeleton:... Continue reading "Structure of garter and grendel model cell membrane" »

Spermatogenesis

Occurs in the seminiferous tubules, which contain interstitial cells that secrete testosterone. The walls of the tubules contain germ cells. As they multiply, they move towards the end until they mature to become spermatozoa.

Oogenesis

Takes place in the ovaries and is divided into two stages:

1. Fetal Development: The female develops immature ova while still an embryo in the mother's womb. Each ovum is surrounded by cells to form structures called follicles. Follicles with immature ova inside stop developing until the woman reaches puberty.
2. Ovarian Cycle: Occurs in cycles of approximately 28 days. Follicles grow, and the ovum inside matures. The release of the mature ovum from the ovary is called ovulation. Typically, females ovulate

Fat vs. CHO

CHO is both aerobic and anaerobic, BUT it has limited stores. It does, however, have a greater energy yield per unit of O2 (fat is about 10% less).

Sparing CHO

Sparing CHO by upregulating lipid oxidation should be advantageous. This leads to:

• More lipid oxidation
• Decreased sympathetic nervous system activity (recruitment of CHO)
• Increased mitochondrial volume and enzymatic adaptations
• Reduction in signals that activate major CHO metabolic enzymes

In lower exercise intensity, more FFA and TG are present in plasma. The more intense the exercise becomes, the more glycogen/glucose is used. At ~62% of VO2 max, the highest lipid oxidative rate is experienced.

Nutritional Strategies to Improve Lipid Oxidation

• High-fat diets: long term vs. short