Notes, summaries, assignments, exams, and problems for Biology

Plant Nutrition Fundamentals

Photosynthesis Definition

Photosynthesis is the process by which plants manufacture carbohydrates from raw materials using energy from light.

Photosynthesis Word Equation

The word equation for photosynthesis is: carbon dioxide + water → (in the presence of light and chlorophyll) → glucose + oxygen.

Photosynthesis Balanced Equation

The balanced chemical equation for photosynthesis states that the combination of carbon dioxide, water, and light energy produces a carbohydrate (glucose) and oxygen.

The chemical formula is: 6CO₂ + 6H₂O + Light Energy → C₆H₁₂O₆ + 6O₂.

Chlorophyll's Role in Energy Transfer

Chlorophyll transfers light energy into chemical energy stored in molecules, enabling the synthesis of... Continue reading "Plant Nutrition and Photosynthesis Essentials" »

Cellular Respiration

1. Definition and Chemical Equation

Cellular respiration is the chemical reaction in which glucose and oxygen are converted into water, carbon dioxide, and energy (ATP). The balanced chemical equation for cellular respiration is: C₆H₁₂O₆ + 6 O₂ --> 6 CO₂ + 6 H₂O + ATP

2. Location of Respiration

Cellular respiration takes place in the mitochondria of living cells.

3. Phases of Respiration and ATP Production

Cellular respiration occurs in three stages: glycolysis, the Krebs cycle, and electron transport. Glycolysis takes place in the cytoplasm and results in a net gain of two ATP molecules.

4. ATP and Energy Production

ATP provides energy to the cell when it is broken down into ADP (adenosine diphosphate) and inorganic phosphate,... Continue reading "Cellular Respiration and Cell Cycle: Key Concepts and Processes" »

1. Central Nervous System

• Brain: Protected by the cranium and divided into:
  • Cerebrum: Interprets information from sense organs, controls language, memory, and thought. It produces voluntary responses.
  • Cerebellum: Controls basic movements and helps maintain balance.
  • Brain Stem: Controls involuntary movements.
• Spinal Cord: Protected by the vertebral column. It sends signals to and from the brain and facilitates involuntary responses or reflexes.

2. Autonomic Nervous System

• Sympathetic: Stimulates organs in case of emergency.
• Parasympathetic: Maintains the functioning of the body.

3. Neurons

Neurons are specialized cells of the nervous system that transmit nerve impulses.

4. Synaptic Transmission

The nerve impulse is transmitted from one neuron to another... Continue reading "Human Nervous and Endocrine Systems: Functions and Processes" »

Common Circulatory System Disorders

• Thrombosis: Occurs when a blood clot causes a blockage in a blood vessel, which can lead to a heart attack or stroke.
• Leukaemia: A type of cancer characterized by an excess of white blood cells.
• Anaemia: A condition where there are not enough red blood cells in the body.
• Arteriosclerosis: Occurs when artery walls become harder due to the buildup of fats and cholesterol.
• Atherosclerosis: When plaque on an artery wall prevents blood from flowing through the artery.
• Myocardial Infarction: Commonly known as a heart attack, caused by a blockage of blood flow in one of the heart's coronary arteries.
• Hemophilia: A hereditary, inherited condition where blood cannot clot properly because of a lack of blood-clotting proteins

Muscles of the Head and Neck

Facial Muscles

• Frontalis
• Orbicularis oculi
• Nasalis
• Zygomaticus major
• Zygomaticus minor
• Levator labii superioris
• Levator anguli oris
• Orbicularis oris
• Depressor labii inferioris
• Depressor anguli oris
• Mentalis
• Buccinator
• Occipitalis

Muscles of Mastication

• Masseter
• Temporalis

Neck Muscles

• Platysma
• Sternocleidomastoid
  • Origin: Sternum and clavicle
  • Insertion: Mastoid process of the temporal bone
  • Action: (Not specified)
  • Nerve: CN XI (Accessory nerve)
• Omohyoid
• Sternohyoid
• Sternothyroid
• Thyrohyoid
• Scalenes

Anatomy of the Eye

Extrinsic Eye Muscles

• Superior rectus: CN III (Oculomotor nerve)
• Inferior rectus: CN III (Oculomotor nerve)
• Lateral rectus: CN VI (Abducens nerve)
• Medial rectus: CN III (Oculomotor nerve)
• Superior oblique: CN IV (Trochlear nerve)
• Inferior

Why Humans Need to Eat

• Molecules in food contain chemical energy that cells use to produce ATP (Adenosine Triphosphate).
• Food supplies raw materials your body needs to build and repair tissues.

Six Essential Nutrients the Body Needs

The six essential nutrients required by the body are:

• Carbohydrates
• Water
• Proteins
• Fats (Lipids)
• Vitamins
• Minerals

Saturated vs. Unsaturated Fats

Similarities

Both saturated and unsaturated fats are lipids made from glycerol and fatty acids (chains of carbon and hydrogen molecules).

Differences

• Saturated fats are typically solids at room temperature.
• Unsaturated fats are usually liquids at room temperature.

Using Food Labels for a Balanced Diet

Food labels are crucial for planning a healthful diet. They help consumers determine if... Continue reading "Essential Nutrients and Human Body Functions" »

Ecosystem

An ecosystem is a community of plants and animals (living things) that interact with each other and their natural surroundings, including non-living things such as rocks, water, and air. Each ecosystem is sustained by a flow of energy through it and the recycling of nutrients within it.

Community

When plants and animals live together, they form a community.

Photosynthesis

Photosynthesis is the process in which plants absorb CO₂ from the air and convert it into sugar using the sun's energy.

Biomes

Biomes are large ecosystems at the global scale where the climate and vegetation are uniform.

Xerophytic Plants

Xerophytes are plants that have adapted by altering their physical structure to survive in harsh climates. These plants exhibit several... Continue reading "Introduction to Ecosystems and Ecology" »

The Interaction Function

The interaction function enables people to perceive changes and stimuli that occur both inside their bodies and their environment, to interpret or process them and generate coordinated responses in order to survive.

1.1 Perceiving Stimuli

The interaction function can be divided into 3 stages: perception of stimuli, processing of the information and generation of responses.

A stimulus is a physical or chemical change that takes place outside or inside the body and triggers a response in it.

Our bodies contain specialist cells, called receptors, which perceive stimuli and send the information they detect to the coordination centres.

Types of Receptors

• Internal receptors perceive changes inside the body, such as a rise in blood

Absorption by the Roots

Key Biological Definitions

1. Imbibition: It is the phenomenon by which a living or a dead cell absorbs water through surface attraction.
2. Diffusion: It is the free movement of molecules of a substance from a region of higher concentration to lower concentration when the two are in direct contact.
3. Osmosis: It is the process of movement of water molecules from a region of higher concentration to a region of lower concentration through a semi-permeable membrane.
4. Endosmosis: It is the inward diffusion of water through a semi-permeable membrane when the surrounding solution is less concentrated.
5. Exosmosis: It is the outward diffusion of water through a semi-permeable membrane when the surrounding solution is more concentrated.
6. Osmotic