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

Plant Anatomy and Physiology Basics

• Xylem: Dead cells that help plants transport water and minerals.
• Starch: An insoluble molecule created by plants from glucose.
• Photosynthesis Products: Oxygen and Glucose (these are also the reactants of respiration).
• Stomata Diffusion: Oxygen gas diffuses out of the stomata.
• Potassium: A mineral salt needed to help plants absorb water.
• Root Hair Cells: Specialized cells responsible for absorbing water and mineral salts.
• Transpiration: The process of water evaporation from plants.
• Soil Absorption: Plants absorb water and mineral salts from the soil.
• Chloroplast: This organelle requires carbon dioxide as a reactant and produces oxygen as a product.
• Nitrogen: A mineral salt essential for making proteins in a plant.
• Cellular

Reproduction in Flowering Plants

The reproduction of flowering plants involves several key steps:

• Pollination: Pollen is transferred from the male stamen to the female stigma. Pollen is carried by insects or the wind.
• Fertilization: When pollen lands on a stigma of the same species, the pollen grain grows a tube to join with the female sex cell (gamete), known as the ovule.
• Seed Dispersal: After fertilization, the flower’s petals fall off and a fruit usually forms from the ovary. The fertilized ovules form seeds, which are dispersed by wind or animals.
• Seed Germination: Seeds begin to grow when temperature, air, and water conditions are optimal.

Sexual Reproduction in Animals

Sexual reproduction requires two individuals of different sexes, each... Continue reading "Biological Reproduction in Plants and Animals Explained" »

Understanding Cancer: Types and Origins

This section introduces various types of cancers and their primary sites of origin within the body, providing foundational knowledge on disease classification.

Common Cancer Types and Their Primary Sites

• Melanoma: Originates in the skin, often from pigment-producing cells.
• Leukemia: Affects white blood cells, typically originating in the bone marrow.
• Carcinoma: Arises from epithelial cells, which line internal organs or cover the skin.
• Sarcoma: Develops in connective tissues, such as bone, cartilage, fat, muscle, or blood vessels.
• Lymphoma: Affects cells and tissues of the immune system, particularly lymphocytes.

Prokaryotic vs. Eukaryotic Cells: Key Differences

Explore the fundamental distinctions between prokaryotic... Continue reading "Core Biology Concepts: Cells, Genetics, and Disease Foundations" »

The cell is the basic unit of which they are made all living things. It is the smallest unit capable of performing all the functions that characterize a living being.

Depending on whether a body is formed by one or more cells can be:

Unicellular organisms. They consist of a single cell that performs all the functions necessary for survival. Sometimes, several single-celled organisms living together colonies. (like amoeba)

Multicellular organisms. Consist of multiple cells that lose the ability to survive alone. Each cell performs a specific task, and all work together to survive the body (such as plants and animals). Our body is composed of a large number of cells. People are multicellular beings.

The cells in our body can have different shape... Continue reading "The cell, the respiratory system, the organelles, gases, diffusion, active transport ..." »

Spine Structure and Biomechanics

Primary Functions of the Spine

• Support and movement of the trunk.
• Protection of the spinal cord.
• Absorption of shock between the ground and the brain.

Vertebral Column Composition

The vertebral column consists of 33 vertebrae:

• 7 Cervical vertebrae
• 12 Thoracic vertebrae
• 5 Lumbar vertebrae
• 5 Fused Sacral vertebrae
• 4 Fused Coccygeal vertebrae

The Motion Segment

A motion segment consists of two adjacent vertebrae and the intervening soft tissue. Each segment contains three articulations:

• The Intervertebral Disc (a symphysis joint).
• The right and left Facet Joints (gliding synovial joints).

Intervertebral Discs

These are fibrocartilage structures connecting adjacent vertebrae, accounting for 20–25% of the spine's total height.

Annulus

Introduction

Enzymes are biological catalysts that accelerate chemical reactions in living organisms without being consumed. They are mostly proteins, although some RNA molecules (ribozymes) also exhibit catalytic activity. Enzymes play a crucial role in metabolism, digestion, energy production, DNA replication, and numerous other biological processes. Since thousands of enzymes have been discovered, a systematic method of naming and classifying them became necessary. The nomenclature and classification of enzymes are regulated by the International Union of Biochemistry and Molecular Biology (IUBMB) through the Enzyme Commission (EC).

Enzyme Nomenclature

Meaning of Enzyme Nomenclature

Enzyme nomenclature refers to the systematic naming of enzymes... Continue reading "Enzyme Nomenclature and Classification: A Complete Reference" »

Chemistry Fundamentals and Reactions

Chemical Bonding Types

• Ionic Bonding: Metal + Non-metal → Electrons are transferred.
• Covalent Bonding: Non-metal + Non-metal → Electrons are shared.

Chemical Naming Conventions

• Ionic Naming: Metal + Non-metal (ending in “-ide”). Use Roman numerals for multivalent metals. Includes polyatomic ions.
• Molecular Compounds: Use prefixes (mono-, di-, tri-, etc.).
• Diatomic Elements: H₂, O₂, F₂, Br₂, I₂, N₂, Cl₂.

Properties of Compounds

• Ionic Compounds: Solid state, high melting/boiling points, conducts electricity when dissolved (aqueous).
• Molecular Compounds: Low melting/boiling points, poor electrical conductors.

Balancing Chemical Equations

The process follows the Law of Conservation of Mass:

1. Word Equation
2. Skeleton

Nervous System Anatomy

• Functions:

  • Controls perception (sight, touch, hearing, taste).
  • Maintains homeostasis (e.g., blood pressure, body temperature).

• Divisions:

  • Central Nervous System (CNS): Brain & spinal cord (processes information and sends responses).
  • Peripheral Nervous System (PNS): Motor & sensory neurons connecting the CNS to the rest of the body.

• PNS Subdivisions:

  • Somatic Nervous System: Controls voluntary movement (e.g., moving hands).
  • Autonomic Nervous System: Controls involuntary functions (e.g., heart rate).
    • Sympathetic Division (Fight or Flight): Increases alertness, heart rate, etc.
    • Parasympathetic Division (Rest & Digest): Slows heart rate, promotes digestion, etc.

• Structural Differences (Autonomic):

  • Parasympathetic: Long preganglionic