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

Unit 1: Cellular Metabolism and Cell Types

Catabolism and Anabolism

Catabolism refers to all chemical reactions where substances are broken down into simpler ones, releasing energy.

• Cellular respiration: C₆H₁₂O₆ + 6O₂ (glucose) → 6CO₂ + 6H₂O + Energy (ATP)

Anabolism refers to all the chemical reactions where simple substances are joined together to form more complex ones.

• Photosynthesis: H₂O + CO₂ + Sunlight → C₆H₁₂O₆ + 6O₂

Heterotrophic Nutrition

Heterotrophic nutrition: Heterotrophic organisms cannot synthesize organic compounds from inorganic compounds. They incorporate organic matter which has been made by other organisms.

1. Some glucose molecules are used in cellular respiration and others are used in other processes.
2. Cellular respiration takes

Accessory Digestive Organs

• Salivary Glands: Parotid, sublingual, and submandibular.
• Tongue/Teeth
• Liver: Produces bile (a fat emulsifier), stores vitamins A, E, D, and K, and aids in detoxification.
• Gallbladder: Stores and concentrates bile.
• Pancreas: Located posterior to/under the stomach. Produces insulin (for transport of sugar into cells) and pancreatic juices capable of breaking down proteins (protease), carbohydrates (amylase), and lipids (lipase). These enzymes pass into the duodenum (small intestine) through the pancreatic duct.

Terms

• Digestion: Process of changing food to a state where it can be used by the body.
• Metabolism: Includes all of the processes involved in the body's use of nutrients.
• Catabolism: Breaking down of body cells or substances,

Cellular Respiration: Definition and Function

Respiration is the fundamental process in which glucose, oxygen, and fatty acids are transformed inside the cell into water, carbon dioxide, and energy (ATP). The primary goal is to convert glucose and oxygen into usable energy.

• It happens inside the cells, specifically within the mitochondria.
• Mitochondria are often described as the site of the "burning of food."
• Oxygen is essential to combine with glucose to facilitate this energy transformation.

Understanding Metabolic Rate (MR)

The Metabolic Rate (MR) is an average measure of the amount of energy that a person needs daily. The MR is typically higher in an active person compared to a sedentary individual.

Energy is required constantly, even while sleeping,...

Reproduction

• Asexual reproduction: Requires only one parent.
• Sexual reproduction: Requires two parents, female and male.

Asexual Reproduction in Plants

1. Spore formation: The plant produces small unicellular structures called spores that become new individuals without attaching themselves to other cells.
2. Vegetative reproduction:
   • Bulbs: Underground stems (e.g., onion or garlic).
   • Stolons: Aerial stems that root when they touch the ground and produce new stems (e.g., strawberry).
   • Stem tubers: Subterranean stems (e.g., potato).

Asexual Reproduction in Animals

• Gemmation or Budding: A small bump or bud appears on the body of the progenitor; it grows and takes on the form of the adult (e.g., sponges).
• Fragmentation: A new organism grows from a fragment of the

Ecological Factors and Environmental Impact

Ecological factors are characteristics of the environment that affect living things. There are two main types:

• Biotic factors: The organisms that share the same natural environment.
• Abiotic factors: Physical and chemical conditions such as sunlight, temperature, oxygen content, water, and the concentration of salts and minerals.

The Role of Limiting Factors

Each species has specific requirements to develop normally. A limiting factor is a factor that is above or below the point at which an organism cannot develop properly. For example, in arid zones, water is a limiting factor for plants.

Adaptation of Organisms to the Environment

Organisms must adapt to the ecological factors of their environment in order...

1. Vital Functions of Living Beings

Vital functions refer to the specific actions that support life. There are three main functions:

• Nutrition function: Living beings obtain the matter and energy necessary to sustain life through this process.
• Interaction function: Living beings relate to their surrounding environment.
• Reproduction function: Individual living beings are produced, which ensures the perpetuation of species.

2. Biomolecules: The Building Blocks of Life

Biomolecules are the building blocks of life and perform important functions in living organisms. Organic biomolecules are exclusive to living beings and consist of three main types:

Carbohydrates

These are the most abundant organic compounds, also known as saccharides. Carbohydrates are...

Key Genetics Definitions

Definitions:

• Dominant (an allele that hides the effect of a weaker allele)
• Allele (different forms of the same gene)
• Gene (a fragment of DNA that codes for one protein)
• Recessive (an allele whose effect is hidden by a dominant allele)
• Genotype (the types of genes in an individual)

DNA Structure

History

James Watson and Francis Crick discovered the structure of DNA. They proposed it because of the work of others, notably Rosalind Franklin, who had been researching the structure of a number of substances using X-ray diffraction techniques. Watson and Crick proposed the double helix structure for DNA.

Structure

A DNA molecule is made from a polynucleotide molecule that contains two strands of nucleotides. DNA has 4 bases: adenine...

Sensory Receptors

Sensory receptors are structures formed by nerve cells specialized to capture and transform stimuli into nerve impulses. The receptors are classified as:

• Chemoreceptors: Sensitive to chemicals.
• Mechanoreceptors: Sensitive to mechanical stimuli such as touch, pressure, sound, or gravity.
• Photoreceptors: Sensitive to light.
• Thermoreceptors: Sensitive to changes in temperature.
• Nociceptors: Sensitive to heavy pressure and responsible for pain.

Receptors can also be classified according to their location:

• Internal receptors: Located inside the body, particularly in the viscera. Responsible for collecting information from internal organs.
• External receptors: Located on the surface of the body. Responsible for collecting external stimuli

Anatomy and Function of the Human Digestive System

The digestive system is responsible for breaking down food and absorbing nutrients. Its primary components include:

• Mouth
• Salivary Glands
• Pharynx
• Esophagus
• Diaphragm (related structure)
• Liver
• Stomach
• Pancreas
• Gallbladder
• Small Intestine (I. Delgado)
• Large Intestine (I. Grueso)
• Appendix
• Rectum and Anus

Insalivation (Saliva Production)

When food is introduced into the mouth, the salivary glands begin to produce saliva, a watery fluid essential for initial digestion.

The Stomach and Chyme Formation

The food bolus remains in the stomach for approximately 3 to 4 hours. Here, it is mixed thoroughly with gastric juice, a secretion produced by glands lining the inner wall. The resulting mixture is called chyme. Gastric...