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.