Comprehensive Biology Study Guide: Cells, Tissues, and Human Body Systems

Posted on Oct 27, 2024 in Biology

Cell Biology

Cell Structures and Functions

Cell Organelles

  • Mitochondria: Oval-shaped organelles that provide energy to the cell.
  • Endoplasmic Reticulum (ER): A network of interconnected sacs and channels involved in protein and lipid synthesis.
    • Rough ER: Studded with ribosomes, synthesizes proteins.
    • Smooth ER: Lacks ribosomes, synthesizes lipids and detoxifies substances.
  • Vacuoles: Store water, nutrients, and waste products.
  • Lysosomes: Break down cellular waste and debris.
  • Cytoskeleton: A network of protein filaments that provides structural support and facilitates cell movement.
  • Centrioles: Involved in cell division.
  • Ribosomes: Sites of protein synthesis.
  • Golgi Apparatus: Modifies, sorts, and packages proteins for secretion.

Nucleus

  • Nuclear Envelope: A double membrane that surrounds the nucleus and regulates the passage of molecules between the nucleus and cytoplasm.
  • Nucleoplasm: The fluid inside the nucleus.
  • Chromatin: DNA and associated proteins that condense to form chromosomes during cell division.
  • Nucleolus: Site of ribosome synthesis.

Cellular Processes

  • Energy Production: Cells generate energy through cellular respiration.
  • DNA Replication: Cells replicate their DNA before cell division.
  • Protein Synthesis: Cells synthesize proteins based on the instructions encoded in their DNA.
  • Transport: Cells transport molecules within the cell and across the cell membrane.
  • Secretion: Cells secrete substances, such as hormones and enzymes.
  • Metabolism: The sum of all chemical reactions that occur within a cell.
    • Catabolism: Breakdown of complex molecules into simpler ones, releasing energy.
    • Anabolism: Synthesis of complex molecules from simpler ones, requiring energy.

Tissues

Epithelial Tissue

  • Function: Covers body surfaces, lines organs and cavities, and forms glands.
  • Types:
    • Covering Epithelium: Forms protective layers.
    • Glandular Epithelium: Secretes substances.

Connective Tissue

  • Function: Supports and connects different tissues and organs.
  • Types:
    • Loose Connective Tissue: Fills spaces between organs and tissues.
    • Dense Connective Tissue: Forms tendons and ligaments.
    • Cartilage: Provides support and flexibility.
    • Bone: Provides support and protection.
    • Blood: Transports oxygen, nutrients, and waste products.

Muscle Tissue

  • Function: Enables movement.
  • Types:
    • Skeletal Muscle: Voluntary movement.
    • Cardiac Muscle: Involuntary contraction of the heart.
    • Smooth Muscle: Involuntary movement of internal organs.

Inorganic and Organic Substances

Inorganic Substances

  • Water: The most abundant compound in living organisms.
  • Mineral Salts: Important for various bodily functions, including bone formation and nerve impulse transmission.

Organic Substances

  • Carbohydrates: Provide energy.
    • Monosaccharides: Simple sugars like glucose.
    • Disaccharides: Two monosaccharides joined together, like sucrose.
    • Polysaccharides: Complex carbohydrates like starch and glycogen.
  • Lipids: Store energy, insulate, and protect organs.
    • Fats: Solid at room temperature.
    • Oils: Liquid at room temperature.
  • Proteins: Structural components, enzymes, hormones, and antibodies.
    • Amino acids: Building blocks of proteins.
  • Vitamins: Essential organic compounds required in small amounts for various bodily functions.

Digestion and Nutrition

Digestion

  • Mechanical Digestion: Physical breakdown of food.
    • Chewing: Breaks down food into smaller pieces.
    • Peristalsis: Muscular contractions that move food through the digestive tract.
  • Chemical Digestion: Breakdown of food by enzymes.
    • Mouth: Saliva begins carbohydrate digestion.
    • Stomach: Gastric juice breaks down proteins.
    • Small Intestine: Completes digestion and absorbs nutrients.

Functions of Food

  • Plastic Function: Building and repairing tissues.
  • Energy Function: Providing energy for bodily functions.
  • Regulatory Function: Maintaining normal bodily processes.

Genetically Modified Foods

  • Foods whose genetic material has been altered to introduce new traits.

Respiration and Excretion

Cellular Respiration

  • The process by which cells convert glucose and oxygen into energy, carbon dioxide, and water.

Respiratory System

  • Function: Exchange of oxygen and carbon dioxide between the body and the environment.
  • Organs: Nose, pharynx, larynx, trachea, bronchi, lungs.
  • Breathing: Inhalation and exhalation of air.

Excretory System

  • Function: Removal of metabolic waste products from the body.
  • Organs: Kidneys, ureters, bladder, urethra.
  • Urine Formation: Filtration, reabsorption, and secretion.

Circulatory System

Blood

  • Composition: Plasma, red blood cells, white blood cells, platelets.
  • Functions: Transports oxygen, nutrients, hormones, and waste products; regulates body temperature; fights infections.

Blood Vessels

  • Arteries: Carry blood away from the heart.
  • Capillaries: Site of exchange between blood and tissues.
  • Veins: Carry blood back to the heart.

Heart

  • Structure: Four chambers: two atria and two ventricles.
  • Cardiac Cycle: Systole (contraction) and diastole (relaxation).
  • Circulation: Pulmonary circulation (heart to lungs) and systemic circulation (heart to body).

Nervous and Endocrine Systems

Nervous System

  • Organization: Central nervous system (CNS) and peripheral nervous system (PNS).
  • CNS: Brain and spinal cord.
  • PNS: Cranial and spinal nerves.
  • Neuron: Basic unit of the nervous system.
  • Synapse: Junction between two neurons.

Endocrine System

  • Glands: Produce and secrete hormones.
  • Hormones: Chemical messengers that regulate bodily functions.
  • Examples: Pituitary gland, thyroid gland, adrenal glands, pancreas, gonads.

Senses and Movement

Sensory Receptors

  • Types: Mechanoreceptors, thermoreceptors, chemoreceptors, photoreceptors.
  • Touch: Meissner’s corpuscles, Pacinian corpuscles, Ruffini corpuscles, Krause’s end bulbs, free nerve endings.
  • Smell: Olfactory receptors in the nasal cavity.
  • Taste: Taste buds on the tongue.
  • Hearing and Balance: Ears.
  • Vision: Eyes.

Movement

  • Voluntary Acts: Consciously controlled movements.
  • Reflexes: Involuntary, automatic responses to stimuli.
  • Joints: Connect bones.
    • Ligaments: Connect bone to bone.
    • Cartilage: Cushions joints.
    • Synovial Fluid: Lubricates joints.