Final A+P Multiple Choice

Cell Organelles

• Nucleus: Controls cell activities, regulates gene expression, synthesizes ribosomes.
• rER (Rough Endoplasmic Reticulum): Synthesizes proteins.
• SER (Smooth Endoplasmic Reticulum): Synthesizes lipids, detoxifies toxins, stores calcium ions.
• Mitochondria: Produces ATP, the cell's energy currency.
• Golgi Apparatus: Modifies, sorts, and packages proteins and lipids for secretion.
• Lysosomes: Digest macromolecules and microorganisms.
• Centrosomes: Organize microtubules, facilitating cell division.
• Proteosomes: Degrade unneeded or damaged proteins.
• Cytoskeleton: Provides structural support, facilitates movement.

Ribosomes (Free) and Vesicles

• Ribosomes (free): Synthesize proteins used within the cytosol.
• Vesicles: Transport and secrete substances, digest materials.

Homeostasis and Feedback Mechanisms

• Homeostasis: Maintains a stable internal environment despite external changes.
• Positive Feedback: Amplifies a change, moving it further away from the set point (e.g., blood clotting, childbirth).
• Negative Feedback: Counteracts a change, moving the variable back towards the set point (e.g., body temperature regulation).

Atoms and Elements

• Atom: Smallest particle of a substance, cannot be broken down chemically. An atom consists of a nucleus (containing protons and neutrons) and orbital electrons.
• Element: Simple substance made of only one type of atom.

Organic and Inorganic Compounds

• Organic Compounds: Contain carbon; essential components of living organisms (e.g., carbohydrates, proteins, lipids, nucleic acids).
• Inorganic Compounds: Do not contain carbon; common in non-living matter (e.g., water, salts, acids, bases).

Metabolism and Cellular Respiration

• Metabolism: All chemical reactions within a living organism; involves cellular respiration.
• Cellular Respiration: Metabolic pathway where cells break down glucose to produce ATP. This process occurs in four stages: glycolysis, intermediate stage, citric acid cycle (CAC), electron transport chain (ETC).

Enzymes

• Enzymes: Catalysts that accelerate chemical reactions; their activity is regulated by various molecules (activators and inhibitors).

Exergonic and Endergonic Reactions

• Exergonic Reactions: Release energy (e.g., cellular respiration).
• Endergonic Reactions: Absorb energy (e.g., photosynthesis).

Anabolism and Catabolism

• Anabolism: Builds larger molecules from smaller ones.
• Catabolism: Breaks down larger molecules into smaller ones.

Levels of Organization of Life

• Chemical Level: Atoms + Molecules.
• Cellular Level: Cells.
• Tissue Level: Tissues.
• Organ Level: Organs.
• Organ System Level: Multiple organs working together.
• Organismal Level: All body systems functioning independently.

Body Systems

• Integumentary System: Protection, sensation, temperature regulation.
• Skeletal System: Support, movement, protection, and mineral storage.
• Muscular System: Produces body movements.
• Nervous System: Controls muscles and glands; processes information via the CNS and the PNS.
• Endocrine System: Secretes hormones, regulates various processes.
• Cardiovascular System: Transports oxygen, nutrients, hormones.
• Lymphatic System: Transports and filters lymph.
• Respiratory System: Exchanges gases between blood and air.
• Urinary System: Removes waste products.
• Digestive System: Digests, absorbs, and expels products.
• Male Reproductive: Produces sex cells and hormones.
• Female Reproductive: Produces sex cells and hormones.

Plasma Membrane

• Structure: Phospholipid bilayer with hydrophilic heads and hydrophobic tails.
• Functions: Regulates what enters and exits the cell.
• Composition: Lipids (phospholipids, cholesterol), proteins (transport, recognition), carbohydrates.
• Fluidity: Affected by temperature and cholesterol content.
• Polar vs Nonpolar Molecules: Uneven/even distribution of charge.
• Hydrophobic/Hydrophilic: "Water-fearing"/ "water-loving".
• Amphipathic: Both hydrophobic and hydrophilic.

Macromolecules

• Major Macromolecules: Carbohydrates, proteins, lipids, nucleic acids.
• Monomers: Small molecules that bond together to form polymers.
• Polymers: Large molecules composed of monomers, linked by chemical bonds.

Cellular Respiration

• Glycolysis: Breaks down glucose into pyruvate, generating a small amount of ATP and NADH.
• Intermediate Stage: Converts pyruvate to acetyl-CoA, producing NADH.
• Citric Acid Cycle (CAC): Oxidizes acetyl-CoA, producing ATP, NADH, and FADH2.
• Electron Transport Chain (ETC): Uses NADH and FADH2 to generate a large amount of ATP through oxidative phosphorylation.

Membrane Transport

• Passive Transport: Movement of molecules across a membrane without energy input (e.g., diffusion, osmosis).
• Active Transport: Movement of molecules across a membrane against their concentration gradient, requiring energy (e.g., pumps).

Osmosis

• Isotonic Solution: Same concentration of solutes as the cytosol.
• Hypotonic Solution: Lower concentration of solutes than the cytosol.
• Hypertonic Solution: Higher concentration of solutes than the cytosol.

Redox Reactions

• Oxidation: Loss of electrons.
• Reduction: Gain of electrons.

Endomembrane System

• Endoplasmic Reticulum (ER): Manufacturing and modification of proteins and lipids.
• Golgi Apparatus: Modifies, sorts, and packages proteins and lipids for secretion or internal use.
• Vesicles: Transport materials within and between the organelles.
• Lysosomes: Digest materials within the cell.

DNA Structure

• Structure: Double helix composed of nucleotides.
• Components: Base pairs (Adenine-Thymine, Guanine-Cytosine), deoxyribose sugar, phosphate groups.
• Chromatin: DNA complexed with proteins (histones).
• Chromosome: Condensed structure of chromatin.

Transcription and Translation

• Transcription: Synthesis of an RNA molecule from a DNA template.
• Translation: Synthesis of a polypeptide (protein) from an mRNA template.
• Enzymes involved: RNA polymerase.
• Modifications of mRNA: Capping, splicing, adding a poly(A) tail.

Cell Division (Mitosis)

• Phases: Interphase, prophase, metaphase, anaphase, telophase, and cytokinesis.
• Purpose: Cell replication in somatic cells.

Cell Cycle

• Interphase: Cell growth and preparation for division (G1, S, G2 phases).
• Mitosis: Nuclear division (prophase, metaphase, anaphase, telophase).
• Cytokinesis: Cytoplasmic division.

Integumentary System (skin)

• Regions: Epidermis (outer layer), dermis (inner layer), hypodermis (subcutaneous layer).

Nervous System

• CNS (Central Nervous System): Brain and spinal cord, process info.
• PNS (Peripheral Nervous System): Nerves that transmit info. to and from the CNS.
• Structure: Nerves, ganglia, nerve fibers, neuron.
• Sensory neurons: Transmits Sensory input to the CNS.
• Motor neurons: Transmits signals away from the CNS to the effector.
• Types of effectors: Muscle cells (skeletal, smooth, cardiac) and glands.

Structure of Neurons

• Dendrites: Receive signals.
• Axon: Conducts signals away from the cell body.
• Neurotransmitters: Chemical messengers.
• Synapses: Junctions between neurons.

Process of Muscle Contraction

• Nerve impulse: Motor neuron stimulation.
• Excitation-Contraction Coupling: Release of calcium ions.
• Power stroke: Myosin heads bind to actin.
• Relaxation: ATP binds to myosin to detach from actin, pumps calcium back into SR.