Biology Finals Semester 2 Term 3 Notes

Cells and Cell Theory

Characteristics of Life

  • Motion
  • Respiration
  • Sensation
  • Growth
  • Reproduction
  • Excretion
  • Nutrition
  • Adaptation
  • Homeostasis
  • Metabolism
  • Organization

Metabolism

  • Definition: All chemical reactions taking place in the body of an organism.
  • Types:
    • Anabolic: Building up complex substances from simpler substances.
      • Example: Photosynthesis.
      • Photosynthesis: Plants use sun, water, and carbon dioxide to produce food.
    • Catabolic: Breaking down complex substances into simpler ones.
      • Example: Digestion in humans.
      • Digestion and respiration are catabolic processes.

Homeostasis

  • Definition: Keeping the internal environment of an organism stable; maintaining balance.
  • Example: Sweating to regulate body temperature at 3737 degrees Celsius when it is too hot.
  • Example: Feeling thirsty and drinking water to maintain the needed amount of water in the body.

Adaptation

  • A process that enables organisms to become better suited to their environment.
  • Species obtain adaptations through evolution, which occurs over great periods of time.
  • Example: A camel is adapted to live in the desert.
  • Example: A polar bear has thick fur to adapt to live in the poles.

Organization

  • Any living thing is made up of one or more cells.
  • Cells are building units of organisms.
  • Types of Organisms:
    • Unicellular: The whole organism is made up of one single cell.
      • Example: Bacteria.
    • Multicellular: The whole organism is made up of many cells.
      • Example: Animals.

How Did Scientists Study Cells?

  • Scientists study cells and their structure using a tool known as the microscope.
  • Microscopes are tools used to magnify a sample to investigate its structure.
  • Types of Microscopes:
    • Compound Light Microscope
    • Electron Microscope

Two Types of Cells

  • Prokaryotes
  • Eukaryotes

Prokaryotic Cell Structure

  • Capsule
  • Pilus
  • Cell wall
  • Plasma membrane
  • Nucleoid (DNA)
  • Cytoplasm
  • Ribosomes
  • Flagellum

Eukaryotic Cell Structure

  • Rough Endoplasmic Reticulum
  • Nucleus
  • Mitochondrion
  • Lysosome
  • Ribosomes
  • Nucleolus
  • Smooth Endoplasmic Reticulum
  • Golgi Apparatus

Introduction to Human Body

Organization of an Organism

  • Cell: The smallest structural and functional unit of organisms.
  • Tissue: Group of cells working together to do a specific function.
  • Organ: Group of different tissues working together.
  • Organ System: Different organs working together to do some functions.
  • Organism: A combination of different organ systems that work together.

Body Systems and Their Purposes

  1. Digestive System
    • Breaks down food into simpler molecules that can be used by cells.
    • Eliminates waste (undigested food).
    • The entire digestive process takes between 24 and 33 hours.
  2. Urinary System
    • Eliminates excess salts and water from the body.
    • Regulates the level of water and salts in the body.
  3. Respiratory System
    • Provides oxygen needed for cellular respiration.
    • Removes carbon dioxide from the body.
  4. Circulatory System
    • Transport system in the human body.
    • Transports materials to and from the cells (e.g., food, oxygen to the cells, carbon dioxide, and other wastes away from the cells).
  5. Skeletal System
    • Supports the body.
    • Protects internal organs.
    • Allows movement.
    • Stores mineral reserves.
    • Provides blood cell formation (bone marrow).
  6. Muscular System
    • Allows body movements.
    • Forms organs.
    • Supports the shape of the body.
  7. Nervous System
    • Transmits signals between the brain and the rest of your body.
    • Controls the ability to breathe, see, think, and more.
  8. Integumentary System
    • The skin.
    • Acts as a barrier against infections and injury, protecting the body.
    • Regulates body temperature.
    • Protects against ultraviolet radiation.
  9. Immune System
    • Helps protect the body from disease.
  10. Reproductive System
    • Produces reproductive cells.
    • In females, nurtures and protects the developing embryo.

The Skeletal System

What is a Skeleton?

  • Made up of bones, joints, tissue, and cartilage
  • Functions:
    • Helps us move.
    • Gives the body structure and shape.
    • Holds us upright.
    • Protects our organs.

Bones

  • Made up of living tissues
  • Outer tissue is hard, and the inner tissue is soft.
  • Store nutrients like calcium and fat.

Joints

  • Where two bones meet.
  • Allow our bodies to move freely.

Cartilage

  • A tissue that protects our joints and bones from rubbing against one another (friction).
  • Some cartilages do not have blood or nerves, so it can take a long time for cartilage to repair if it is damaged.

The Muscular System

What do our muscles do?

  • Enable us to move our body parts.
  • Give us our individual shape.
  • Protect and keep in place our abdominal organs.
  • Enable us to maintain good posture.
  • Help in the circulation of our blood.
  • Generate body heat when they contract.

Types of Muscles

  1. Skeletal (Voluntary) Muscles
    • Under our conscious control.
    • Instruct them to perform everyday actions such as walking, running, and jumping.
  2. Smooth (Involuntary) Muscles
    • Work automatically – they are not under our conscious control.
    • Example: Muscles of the digestive system.
  3. Cardiac Muscle
    • A special type of involuntary muscle.
    • Found ONLY in the heart.
    • Contracts regularly, continuously, and without tiring.
    • Works automatically but is under constant nervous and chemical control.
    • Conducts electricity.

How are Muscles Attached to Bones?

  • Muscles are usually attached to 2 or more different bones.
  • Muscle fibers end in a strong, white flexible cord called a TENDON. TENDON attches Muscle to bone.