Biology: DNA and Chromosome Structures

DNA Structure

• DNA is a double helix, resembling a twisted ladder.
• The "sides" of the ladder are made of alternating sugar (deoxyribose) and phosphate molecules.
• The "rungs" of the ladder are pairs of nitrogenous bases: adenine (A) with thymine (T), and guanine (G) with cytosine (C).
• The sequence of these bases determines the genetic code.

Sex Chromosome Structure

• Sex chromosomes determine the sex of an organism.
• Humans have 23 pairs of chromosomes, 22 of which are autosomes, and one pair of sex chromosomes.
• The sex chromosomes are X and Y; females typically have XX and males XY.

Mitosis, Meiosis, Mutation, Non-disjunction

• Mitosis: Cell division resulting in two identical daughter cells. Used for growth and repair.
• Meiosis: Cell division resulting in four genetically diverse daughter cells. Used for sexual reproduction.
• Mutation: A change in the DNA sequence. Can be beneficial, harmful, or neutral.
• Non-disjunction: Failure of chromosomes to separate properly during cell division (meiosis or mitosis). Can lead to abnormal chromosome numbers in offspring.

Atomic Structure and Electron Movement

• Atoms consist of a nucleus containing protons and neutrons, with electrons orbiting the nucleus.
• Electrons occupy specific energy levels (shells) around the nucleus.
• Electrons can move between energy levels by absorbing or releasing energy.

Types of Bonding

• Ionic bonding: Transfer of electrons between atoms, forming ions with opposite charges that attract.
• Covalent bonding: Sharing of electrons between atoms, forming molecules.
• Metallic bonding: Electrons are shared among many atoms in a metal, allowing for properties like conductivity.

Elements

• An element is a pure substance consisting of only one type of atom.
• Elements are organized on the periodic table based on their atomic structure and properties.

Science

• Science is a systematic process of observing, describing, experimenting, and interpreting nature.

Biology

• Biology is the study of living organisms and their interactions with the environment.

Hypothesis

• A testable explanation for an observation or phenomenon.

Types of Chemistry

• Inorganic chemistry: Study of compounds not containing carbon.
• Organic chemistry: Study of compounds containing carbon.
• Physical chemistry: Study of the physical properties and chemical processes of matter.
• Analytical chemistry: Study of the identification and quantification of chemical substances.

Acidity and Basicity

• Acidity: A measure of the concentration of hydrogen ions (H+) in a solution.
• Basicity: A measure of the concentration of hydroxide ions (OH-) in a solution.

Eukaryotic and Prokaryotic Cells

• Eukaryotic cells: Contain a nucleus and other membrane-bound organelles.
• Prokaryotic cells: Lack a nucleus and other membrane-bound organelles.

ATP Function

• ATP (adenosine triphosphate) is the primary energy currency of cells.
• It stores and releases energy for cellular processes.

Filtration, Diffusion, Osmosis, Active Transport

• Filtration: Physical process separating substances based on size.
• Diffusion: Movement of particles from high to low concentration.
• Osmosis: Movement of water across a semipermeable membrane from high to low concentration.
• Active transport: Movement of particles against a concentration gradient, requiring energy.

Reactant, Solution, Precipitate, Product, Compound, Chemical Reaction

• Reactant: Substance that undergoes change in a chemical reaction.
• Solution: Homogeneous mixture of two or more substances. Solvent dissolves solute.
• Precipitate: Solid that forms from a solution during a chemical reaction.
• Product: Substance formed in a chemical reaction.
• Compound: Substance formed from two or more different elements.
• Chemical reaction: Process where substances change to form new substances.

Homogeneous and Heterogeneous Mixtures

• Homogeneous mixtures: Uniform composition throughout (e.g., saltwater).
• Heterogeneous mixtures: Non-uniform composition (e.g., sand and water).

Evolution

• Evolution is the gradual change in the characteristics of a species over many generations.
• Driven by natural selection, where organisms best adapted to their environment survive and reproduce.

Hydrogen Bonding in Water, Carbon Dioxide, and Carbon Monoxide

• Water: Hydrogen bonds between water molecules give water its unique properties.
• Carbon dioxide: Nonpolar molecules, do not form hydrogen bonds.
• Carbon monoxide: Nonpolar molecules, do not form hydrogen bonds.

Mass, Weight, Density, Solid, Liquid, Gas, Matter, Mixture

• Mass: Amount of matter in an object.
• Weight: Force of gravity acting on an object.
• Density: Mass per unit volume.
• Solid: Definite shape and volume.
• Liquid: Definite volume, indefinite shape.
• Gas: Indefinite shape and volume.
• Matter: Anything that has mass and takes up space.
• Mixture: Two or more substances combined without chemical changes.

Bacteria and Viruses Structure and Function

• Bacteria: Prokaryotic organisms with cell walls, capable of independent reproduction and exhibiting diverse metabolic functions.
• Viruses: Non-cellular entities containing genetic material and protein coat. They reproduce within host cells.

Animal Cell Anatomy

• Animal cells possess a nucleus, cytoplasm, cell membrane, and various organelles.

Biological Structures (Smallest to Largest)

• Molecules → Cells → Tissues → Organs → Organ Systems → Organism

Body Systems Function

• Skeletal: Provides support and protection, stores minerals, aids in movement.
• Muscular: Enables movement.
• Respiratory: Exchanges gases (oxygen and carbon dioxide).
• Cardiovascular: Transports nutrients, oxygen, and wastes throughout the body.
• Immune: Protects against disease.
• Integumentary: Forms a protective outer layer.
• Endocrine: Regulates bodily functions via hormones.
• Nervous: Controls bodily functions using electrical signals.
• Reproductive: Facilitates sexual reproduction.
• Digestive: Breaks down food for absorption.

Cardiovascular System Anatomy and Blood Flow

• The cardiovascular system includes the heart, blood vessels (veins, arteries, capillaries), and blood.
• Blood flows from the heart through arteries to the body, then through veins back to the heart.

Blood Components

• Blood comprises plasma, red blood cells (erythrocytes), white blood cells (leukocytes), and platelets (thrombocytes).

Blood Cell Types

• Red blood cells (erythrocytes): Carry oxygen.
• White blood cells (leukocytes): Part of the immune system, fight infection.
• Platelets (thrombocytes): Involved in blood clotting.

Muscle Types

• Skeletal muscle: Voluntary muscle attached to bones.
• Smooth muscle: Involuntary muscle found in internal organs.
• Cardiac muscle: Involuntary muscle found in the heart.

Insulin Function

• Insulin regulates blood glucose levels by promoting the uptake of glucose into cells.

Fertilization, Ovulation, Menstruation

• Fertilization: Fusion of egg and sperm cells.
• Ovulation: Release of an egg from the ovary.
• Menstruation: Shedding of the uterine lining if fertilization does not occur.

Nose, Mouth, Hair, Nails Anatomy and Function

• Nose: Detects smell, filters air.
• Mouth: Ingests food, speech.
• Hair: Protection, insulation, sensory function.
• Nails: Protection of the fingertips.

Plant Categories

• Plants are categorized into various groups based on characteristics, such as flowering or non-flowering plants.

Water Uptake in Plants

• Plants absorb water through their roots, aided by osmosis and root hair cells.

Air Exchange in Leaves

• Leaves facilitate gas exchange (oxygen and carbon dioxide) through stomata.

Plant Cell Structure and Function

• Plant cells contain a cell wall, chloroplasts, and a large central vacuole.

Cellulose Function

• Cellulose provides structural support to plant cell walls.

Plant Pollination

• Plants are pollinated by various agents, such as wind, water, or animals.

Photosynthesis and Respiration

• Photosynthesis: The process by which plants convert light energy into chemical energy (glucose).
• Respiration: The process by which organisms break down glucose to release energy.

Explore the fundamental concepts of DNA structure, sex chromosomes, and the processes of mitosis and meiosis. Learn about how genetic information is carried and how cell division plays a critical role in growth and reproduction. Test your understanding of genetic mutations and non-disjunction.