Honors Biology 9 - Semester 1 Vocabulary Terms

Complete list of vocabuary terms studied and learned in the first semester of honors biology 9

science

organized way of gathering and analyzing evidence about the natural world

observation

process of noticing and describing events or processes in a careful, orderly way

inference

logical interpretation based on prior knowledge or experience

hypothesis

possible explanation for a set of observations or possible answer to a scientific question; an educated guess

controlled experiment

experiment in which only one variable is manipulated

control group

group in an experiment that is exposed to the same conditions as the experimental group except for one independent variable

data

evidence; information gathered from observations

theory

well-tested explanation that unifies a broad range of observations and hypotheses, and enables scientists to make accurate predictions about new situations

DNA

genetic material that an organism inherits from their parents; deoxyribonucleic acid

stimulus

signal to which an organism responds

homeostasis

relatively constant, internal, physical and chemical conditions that organisms maintain

metabolism

the combination of chemical reactions through which an organism builds up or breaks down materials

glycerol and fatty acid

structural components of lipids; also called triglycerides

acid

compound that forms hydrogen ions (H+) in solution; a solution with a pH of less than 7

base

compound that produces hydroxide ions ( OH-) in solution; solution with a pH of more than 7

monomer

small chemical unit that makes up a polymer

polymer

molecules composed of many monomers; make up macromolecules

carbohydrate

compound made up of carbon, hydrogen, and oxygen atoms; type of nutrient that is the major source of energy for the body; examples include starch and sucrose

monosaccharide

simple chemical unit that makes up a polymer of sugar; examples include glucose and fructose

lipid

macromolecule made mostly from carbon and hydrogen atoms; includes fats, oils, and waxes

nucleic acid

macromolecule containing hydrogen, oxygen, nitrogen, carbon, and phosphorus; contain hereditary information used to make proteins

nucleotide

subunit of which nucleic acids are composed; made up of a 5-carbon sugar, a phosphate group, and a nitrogenous base; monomer of nucleic acids, such as DNA or RNA

protein

macromolecule that contains carbon, hydrogen, oxygen, and nitrogen; needed by the body for growth and repair processes

amino acid

compounds with an amino group on one end and a carboxyl group on the other end; monomer of protein

catalyst

substance that speeds up the rate of a chemical reaction

enzyme

protein that acts as biological catalysts; speed up the chemical reactions that take place in the cell

substrate

reactant of enzyme-catalyzed reactions; fits into the enzyme's active site and undergoes a chemical reaction to form a product

active site

a region on an enzyme having a specific shape that binds to a substrate with a complementary shape during a chemical reaction

cell theory

all living things are made of cells, cells are the basic unit of structure and function in living things, and new cells are produced from existing cells

cell membrane

thin, flexible barrier that surrounds the cell and regulates what enters and leaves the cell

nucleus

the control center of the cell

eukaryote

cell containing a true membrane-bound nucleus and organelles

prokaryote

cell lacking a true nucleus and organelles

cytoplasm

both the cytosol fluid and cytoskeleton that fills the cells or fills the space between the nucleus and the cell membrane

organelle

specialized structure that performs important cellular functions within a eukaryotic cell

lipid bilayer

flexible double-layered sheet that makes up the cell membrane and forms a barrier between the cell and its surroundings

selectively permeable

property of biological membranes that allows some substances to pass across while others cannot

diffusion

process by which particles tend to move from an area of high concentration to an area of low concentration

facilitated diffusion

process of diffusion in which molecules pass across the cell membrane through protein channels

aquaporin

water channel protein in a cell

osmosis

diffusion of water through a selectively permeable membrane

osmotic pressure

force that must be applied to prevent osmotic movement across a selectively permeable membrane

receptor

a specific protein on or in a cell that has a specific shape to which a signal molecule can bind

asexual reproduction

Process of reproduction involving a single parent that results in offspring that are genetically identical to the parent

sexual reproduction

Type of reproduction in which cells from two parents unite to form the first cell of a new organism

chromosome

Threadlike structure of DNA and protein that contains genetic information; so-called super-coiled rods of DNA

cell cycle

Series of events in which a cell grows, prepares for division, and divides into two daughter cells

mitosis

Part of eukaryotic cell division in which the cell nucleus divides

chromatin

Substance found in eukaryotic chromosomes that consists of DNA tightly coiled around histone proteins; so-called unraveled form of DNA

cytokinesis

Division of the cytoplasm to form two separate daughter cells

chromatid

One of two identical "sister" parts of a duplicated chromosome

cyclin

One of a family of proteins that regulates the cell cycle in eukaryotic cells

growth factor

One of a group of external regulatory proteins that stimulate growth and division of cells

apoptosis

Process of programmed cell death; cell suicide

cancer

Disorder in which some of the body's cells lose the ability to control growth

embryo

Developing stage of a multicellular organism

differentiation

Process in which cells become specialized in structure and function

stem cell

Unspecialized cell that can give rise to one or more types of specialized cells

Adenosine triphosphate (ATP)

Compound used by cells to store and release energy

Photosynthesis

Process used by plants and other autotrophs to capture light energy and use it to power chemical reactions that convert carbon dioxide and water in to oxygen and energy-rich carbohydrates such as sugars and starches

Chlorophyll

Principle pigment of plants and other photosynthetic organisms

Thylakoid

Saclike photosynthetic membranes found in chloroplasts

Stroma

Fluid portion of the chloroplast outside of the thylakoids

Light-dependent reactions

Set of reactions in photosynthesis that use energy from light to produce ATP and NADPH

Light-independent reactions

Set of reactions in photosynthesis that do not require light; energy from ATP and NADPH is used to build high-energy compound such as sugar; also known as the Calvin Cycle

Electron transport chain

Series of electron carrier proteins that shuttle high-energy electrons during ATP-generating reactions

Cellular respiration

Process that releases energy by breaking down glucose and other food molecules in the presence of oxygen

Aerobic

Process that requires oxygen

Anaerobic

Process that does not require oxygen

Glycolysis

First set of reactions of cellular respiration in which a molecule of glucose is broken down into two molecules of pyruvic acid

Kreb's Cycle

Second stage of cellular respiration in which pyruvic acid is broken down into carbon dioxide in a series of energy-extracting reactions

Matrix

Innermost compartment of the mitochondrion

Fermentation

Process by which cells release energy in the absence of oxygen

biotic factor

any living thing or previously living thing in an ecosystem that affects life (live or dead organisms)

abiotic factor

any nonliving material in an ecosystem (ex. water, rocks, soil, air)

trophic level

each step in a food chain or food web

heterotroph

organism that consumes its food by eating other organisms (ex. human, bear, mouse)

chemosynthesis

process in which chemical energy is used to produce carbohydrates, such as how bacteria at the bottom of the ocean use sulfur compounds to produce their own food

omnivore

organism that obtains energy by consuming both plants and animals

nitrogen fixation

process of converting nitrogen gas into nitrogen compounds that plants can absorb and use

autotroph

an organism that is a producer; organisms that are able to make their own food using the sun's energy or other chemicals (ex. plants and some bacteria)

denitrification

process by which bacteria convert nitrates into nitrogen gas to be returned to the atmosphere

photosynthesis

process used by plants and other autotrophs to capture the sun's energy and use it to power chemical reactions that convert carbon dioxide and water into carbohydrates, such as glucose

limiting nutrient

single essential nutrient that limits productivity in an ecosystem

detritivore

an organism that decomposes dead or decaying material (ex. bacteria, vultures, fungi)

biogeochemical cycle

exchange or circulation of matter through the biosphere between biotic and abiotic factors

decomposer

organism that breaks down and obtains energy from dead organic matter; also known as a detritivore

biomass

the total amount of living material on Earth

Greenhouse effect

Process in which certain gases trap sunlight energy In earth's atmosphere as heat

Tolerance

ability of an organism to survive and reproduce under circumstances that differ from their optimal conditions

Niche

full range of physical and biological conditions in which an organism lives and the way in which the organism uses the conditions

Competitive Exclusion Principle

principle that states that no two species can occupy the same niche in the same habitat at the same time

Predation

interactions in which one organism captures and feeds on another organism

Herbivory

interactions in which organisms obtain energy by eating only plants

Keystone species

single species that is not usually abundant in a community yet creates strong control on the structure of a community

Symbiosis

relationship in which two species live close together

Mutualism

symbiotic relationship in which both species benefit from the relationship

Parasitism

symbiotic relationship in which one organism lives on or inside another organism an harms it

Commensalism

symbiotic relationship in which one organism benefits and the other is neither helped nor harmed

Ecological succession

series of gradual changes that occur in a community following a disturbance