Notes, summaries, assignments, exams, and exercises for Biology for Secondary education

Understanding Feeding and Nutrition

Feeding vs. Nutrition: Key Differences

• Feeding (Eating): Subjective, voluntary, and conscious actions related to consuming food.
• Nutrition (Nourishing): Involuntary, unconscious, and objective processes involving the assimilation of nutrients by the body.

Essential Nutrients: Organic and Inorganic

Nutrients are classified based on whether they contain carbon (C).

Inorganic Nutrients

These nutrients do not contain carbon (C). They are vital for bodily functions.

• Water: Essential for all chemical reactions in the body.
• Mineral Salts: Essential inorganic nutrients needed in small amounts.

Organic Nutrients

These nutrients contain carbon (C). They provide energy and building blocks for the body.

• Carbohydrates: Provide fast

The Menstrual and Ovarian Cycles

Menstruation: This phase begins on the first day of the cycle and lasts 5 to 7 days. If fertilization does not occur, the corpus luteum breaks down and stops producing progesterone. This causes the endometrium to shed, along with the oocyte, resulting in menstruation. If fertilization occurs, the embryo produces a hormone similar to LH (Luteinizing Hormone) to keep the corpus luteum active. It continues producing hormones, preventing menstruation. The oocyte is fertilized and completes oogenesis.

Proliferative Phase: This starts after menstruation and lasts until ovulation. Estrogens from the ovarian follicle stimulate the thickening of the endometrium and the growth of blood vessels.

Secretory Phase: This occurs...

Frog Embryology: Developmental Stages

Frogs reproduce through external fertilization, where the female lays eggs in water, and the male releases sperm over them. Fertilization occurs in the animal hemisphere of the egg. This process forms a diploid zygote. The point of sperm entry determines the gray crescent, which helps in the later development of the body axis.

1. Cleavage: Early Cell Division

The zygote undergoes holoblastic, unequal, and radial cleavage. The first two cleavages are vertical, forming four equal blastomeres. The third cleavage is horizontal but displaced towards the animal pole, resulting in smaller cells (micromeres) in the animal pole and larger cells (macromeres) in the vegetal pole. These divisions continue to form a morula,...

Physiology Assessment Solutions

Blood Composition and Function

• 1. e. A and C: Lungs and Intestines bring in oxygen and nutrients into the blood.
• 2. d. 92%
• 3. a. Fibrinogen
• 4. c. The heme group
• 5. a. One
• 6. d. Leukocytes: Leukocytes (white blood cells) are not dissolved in plasma; they are cells that circulate or reside in tissues.
• 7. d. Erythropoietin: The hormone that stimulates red blood cell production is erythropoietin.
• 8. a. 250,000,000: Each red blood cell contains approximately 250 million hemoglobin molecules.

Hemostasis and Clotting

• 9. b. Fibrinogen: Thrombin converts fibrinogen into fibrin to form blood clots.
• 10. c. Tissue factor: Tissue factor, exposed upon damage, activates plasma proteins in the clotting cascade.
• 11. d. Plasmin: Plasmin dissolves

Biological Organization of the Human Body

The hierarchy of life follows this progression: Atom → Molecule → Cell → Tissue → Organ → Organ System → Organism (Wingspan = Height).

Body Symmetry and Structure

• Radial: Symmetry around a central axis.
• Bilateral: Divided equally across a plane.
• Asymmetrical: Inability to be divided.

Humans exhibit bilateral symmetry and are proportionate.

Functional Principles

Function follows form. For example, the Cell Membrane acts as a Plasma Membrane, while the Cutaneous Membrane acts as skin.

Life Processes and Homeostasis

Essential life functions include:

• Maintenance of Boundaries: Separating internal from external (Integumentary).
• Movement: Muscular and Skeletal systems.
• Responsiveness: Nervous and Endocrine

Theories on the Origin of Life

The primordial soup hypothesis is incapable of explaining the origin of life because the early atmosphere wasn't composed of the gases described by Oparin and Haldane. Also, we know that in the early atmosphere, there was no ozone layer, so it would make the first molecules very unstable because of UV radiation. The hypothesis was supported by the Miller-Urey experiment, which consisted of the following: a mixture of gases was put in a container, and high-voltage electric shocks were applied. Then, gases were condensed in another container, simulating the primitive ocean. Finally, several organic compounds were found in that simulated "primordial soup," including amino acids. As an alternative to the primordial...

Nucleic Acid Structure and Function

• Nucleoside: A part of a nucleotide made up of one sugar (ribose or deoxyribose) and one nitrogenous base (pyrimidine or purine) joined together by N-glycosidic bonds.
• Nucleotide: Simple molecules that form large molecules called nucleic acids. It is formed by a nitrogenous base, sugar, and three phosphate groups.
• Chromatin: Bundles of DNA and proteins; the normal state of the genetic material during interphase.
• Chromosome: Structures formed by the condensation of chromatin that appear when the cell is about to divide.
• Centromere: A bond that joins two sister chromatids; it's where the microtubules are attached to the chromosome during the division process.
• Telomere: The end of the arms of a chromosome, which prevents

Interaction and Homeostasis

Interaction includes a series of processes whose object is to adapt the body to changing conditions in the internal and external environment. It connects and coordinates the different parts of our body so that they work together.

Homeostasis is the process that maintains the body's stability when there are changes in the internal environment. This process works as a feedback device, meaning that when a variation is detected in a particular element, a series of mechanisms in the body start up to make the variation return to its normal state.

Systems Participating in the Interaction Process

• Sensory Organs: Capture the stimulus, which is transformed into a nerve impulse and transmitted to the nervous system.
• Nervous System:

Fibra:Fiber is a complex carbohydrate of plant origin. Humans
cannot digest fiber or use it as a source of energy or
matter, but it is nonetheless essential for the functioning
of the digestive system.

Nutrients:Organic nutrients: are complex molecules produced by

Inorganic nutrients: are simple molecules that can be
found in living organisms, but have not been produced by
them. These nutrients are essential to your body but do
not supply any energy.
○ Minerals (such as calcium and sodium)
○ Water
○ Oxygen

Vitamins:Vitamins are organic components that the body either
cannot produce or produces only in insufficient
quantities.
● These must be obtained from food.
● All vitamins are needed in small quantities and they are
essential for regulating many...

Functions of the Endocrine System

The endocrine system performs several vital roles in maintaining the body's internal environment. Its most important functions include:

• Reproduction
• Metabolism and Energy Balance
• Growth and Development
• Body Defenses
• General Homeostasis: Maintaining water, nutrient, and salt balance in the blood.

While all are critical, homeostasis is often considered the most important as it ensures a stable internal environment for all other processes.

Major Endocrine Glands and Their Hormones

The following table details the primary endocrine glands, the hormones they secrete, and their specific functions: