Biology Semester 1 Final Exam Study Guide for 10th Grade

Observation

The action or process of observing something or someone carefully to gain information.

Hypothesis

A proposed explanation made on the basis of limited evidence as a starting point for further investigation.

Independent variable

The variable that is changed or controlled in a scientific experiment to test its effects on the dependent variable.

Dependent variable

The variable that is measured in an experiment; it is dependent on the independent variable.

Control group

A group in an experiment that does not receive treatment and is used as a benchmark to measure how the other tested subjects do.

Scientific method

A systematic process for pursuing knowledge involving observation, hypothesis formulation, experimentation, data collection, and conclusion.

Metabolism

The sum of all chemical reactions that occur within a biological organism to maintain life.

Homeostasis

The process by which an organism maintains a stable internal environment despite changes in external conditions.

Stimuli

External factors that elicit a response from an organism.

Reproduction

The biological process by which new individual organisms are produced.

Ecosystem

A community of living organisms interacting with their physical environment.

Population

A group of individuals of the same species that live in the same area and interact with one another.

Community

An assemblage of different populations that live together in a defined area.

Biome

A large naturally occurring community of flora and fauna occupying a major habitat.

Biosphere

The global sum of all ecosystems; the zone of life on Earth.

Trophic levels

The hierarchical levels in an ecosystem, comprising producers, consumers, and decomposers.

Producer

Organisms that produce their own food, typically through photosynthesis.

Consumer

Organisms that obtain energy by consuming other organisms.

Decomposer

Organisms that break down dead or decaying organisms, recycling nutrients back into the ecosystem.

Energy pyramid

A graphical representation of the energy flow in an ecosystem, showing the primary producers at the bottom and top-level consumers at the top.

Predation

A biological interaction where one organism, the predator, kills and eats another organism, the prey.

Mutualism

A type of symbiotic relationship where both species benefit.

Commensalism

A type of symbiotic relationship where one species benefits and the other is neither helped nor harmed.

Parasitism

A relationship between two species where one species benefits at the expense of the other.

Interspecific competition

Competition between different species for the same resources.

Intraspecific competition

Competition among individuals of the same species for limited resources.

Cell membrane

A biological membrane that separates and protects the interior of all cells from the external environment.

Organelles

Specialized structures within a cell that perform specific functions.

Phospholipid

A type of lipid that forms a bilayer in cell membranes, consisting of a hydrophilic head and hydrophobic tails.

Cholesterol

A type of fat found in your blood that is necessary for building cells but can cause health problems in excess.

Semipermeable membrane

A membrane that allows certain molecules or ions to pass through it by diffusion and occasionally by facilitated diffusion.

Diffusion

The process by which molecules spread from an area of high concentration to an area of low concentration.

Osmosis

The movement of water across a semipermeable membrane from an area of low solute concentration to an area of high solute concentration.

Active transport

The process of moving molecules across a cell membrane through the use of cellular energy.

Isotonic

A solution that has the same concentration of solutes as another solution.

Hypertonic

A solution that has a higher concentration of solutes compared to another solution.

Hypotonic

A solution that has a lower concentration of solutes compared to another solution.

Chlorophyll

The green pigment found in plants that is essential for photosynthesis as it absorbs light energy.

Thylakoid

A membrane-bound compartment inside chloroplasts and cyanobacteria where the light-dependent reactions of photosynthesis occur.

Stroma

The fluid-filled space inside the chloroplast where the Calvin cycle takes place.

Light-dependent reactions

The part of photosynthesis that converts solar energy into chemical energy, producing ATP and NADPH.

Calvin Cycle

The set of chemical reactions that take place in chloroplasts during photosynthesis; it converts carbon dioxide and other compounds into glucose.

ATP

A nucleotide that acts as the primary energy carrier in all living organisms.

NADPH

An electron carrier that provides the high-energy electrons needed to make carbon-hydrogen bonds in the Calvin Cycle.

Carbon fixation

The process of converting inorganic CO2 into organic compounds by photosynthetic organisms.

Glycolysis

The process of breaking down glucose to extract energy, yielding 2 ATPs.

Pyruvate

The end product of glycolysis, which is further processed in cellular respiration.

Krebs Cycle

A series of chemical reactions used by all aerobic organisms to generate energy through the oxidation of acetate derived from carbohydrates, fats, and proteins.

Electron transport chain

A series of complexes that transfer electrons from electron donors to electron acceptors via redox reactions, releasing energy.

Aerobic respiration

A form of cellular respiration that requires oxygen to produce ATP.

Anaerobic respiration

A form of respiration used by some organisms that does not require oxygen.

Fermentation

A metabolic process that converts sugar to acids, gases, or alcohol in the absence of oxygen.

Mitosis

The process of cell division in which the nucleus divides, resulting in two identical daughter cells.

Cytokinesis

The division of the cytoplasm to form two separate daughter cells after mitosis.

Chromosomes

Thread-like structures made of DNA that contain the genetic information.

Chromatids

Identical copies of a chromosome that are joined together by a centromere.

Cell cycle phases

The series of phases that a cell goes through in order to divide and replicate.

Checkpoints

Regulatory points in the cell cycle that monitor and control the progression of cell division.

Apoptosis

The process of programmed cell death that occurs in multicellular organisms.

Spindle fibers

Structures that separate the chromosomes during cell division.