Honors Biology Semester 1 Exam Vocabulary

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biology

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science of life; examines how living things interact, how systems function, and how they function at a molecular level

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organism

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anything that has or once had all the characteristics of life

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organization

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orderly structure shown by living things

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growth

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process that results in mass being added to an organism; may include formation of new cells and new structures

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development

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changes an organism undergoes in its lifetime before reaching its adult form

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reproduction

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production of offspring

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species

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group of organisms that can interbreed and produce fertile offspring

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stimulus

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any change in an organism's internal or external environment that causes the organism to react

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response

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organism's reaction to a stimulus

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homeostasis

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regulation of an organism's internal environment to maintain conditions needed for life.

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adaptation

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inherited characteristics of a species that develops over time in response to an environmental factor, enabling the species to survive

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science

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a body of knowledge based on the study of nature

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theory

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explanation of a natural phenomenon based on many observations and investigations over time

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law

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a description of relationships under certain conditions in nature

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peer review

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a process in which the procedures used during an experiment may be repeated and the results are evaluated by scientistswho are in the same field or are conducting similar research

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ethics

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a set of values

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observation

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orderly, direct information gathering about a natural phenomenon

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inference

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assumption based on prior experience

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scientific method

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a series of problem solving procedures that might include, observations, forming a hypothesis, experimenting, gathering and analyzing data, and drawing conclusions

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hypothesis

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testable explanation of a situation

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experiment

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procedure performed in a controlled setting to test a hypothesis and collect precise data

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control group

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in a controlled experiment, the group not receiving the factor being tested

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experimental group

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The group receiving the factor being tested

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independent variable

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the one factor that can be changed in a controlled experiment or the one tested

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dependent variable

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factor being measured in a controlled experiment; its value changes because of changes to the independent variable

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constant

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a factor that remains fixed during an experiment while the independent and dependent variables change

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data

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quantitative or qualitative information gained from scientific investigation

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metric system

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measurement system whose divisions are powers of ten

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SI

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system of measurements used by scientists; international system of units

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cell

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basic unit of structure and organization of all living organisms

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cell theory

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states that organisms are made of one or more cells and cells are the basic unit of life and all cells come only from other cells

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plasma membrane

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holds cell together, controls what goes in and out

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organelle

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specialized internal cell structure that carries out specific cell functions such as protein synthesis and energy transformation

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eukaryotic cell

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unicellular organism with membrane-bound nucleus and organelles

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nucleus

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found in middle, the command/control center or the brain

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prokaryotic cell

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microscopic, unicellular organism without a nucleus or other membrane-bound organelles

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selective permeability

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property of the plasma membrane that allows it to control movement of substances into or out of the cell

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phospholipid bilayer

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plasma membrane layers composed of phospholipid molecules arranged with polar heads facing the outside and nonpolar tails facing the inside

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transport protein

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protein that moves substances or wastes through the plasma membrane

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fluid mosaic model

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a plasma membrane with components constantly in motion, sliding past one another within the lipid bilayer

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cytoplasm

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jelly-like fluid, allows things to move

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cytoskeleton

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suppporting network of protein fibers that provide a framework for the cell within the cytoplasm

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ribosome

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found on the ER, makes proteins

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nucleolus

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inside nucleus, makes ribosomes

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endoplasmic reticulum

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passageway around nucleus

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golgi apparatus

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gift wrapper, make vacuoles, keeps clean and orderly

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vacuole

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storage area, stores water, food, and wastes, bigger in plans because it supports cell wall

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lysosome

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vesicle that uses enzymes to digest excess or worn-out cellular substances

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centriole

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in animal cells only, star shaped cylinder, help cells divide

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mitochondrion

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powerhouse, makes ATP

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chloroplast

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absorbs sunlight to photosynthesize, green, plants only

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cell wall

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in plant cells only, provides structure and support

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cilium

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short, hairlike projection that functions in cell movement

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flagellum

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long, tail-like projection with whiplike or propellar motion that helps a cell move

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diffusion

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net movement of particles from an area of higher concentration to an area of lower concentration

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dynamic equilibrium

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condition of continuous, random movement of particles but no overall change in concentration of materials

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facilitated diffusion

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passive transport of ions and small molecules across the plasma membrane by transport proteins

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osmosis

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diffusion of water across a selectively permeable membrane

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isotonic solution

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a solution with the same concentration of water and solutes as inside a cell, resulting in the cell retaining its normal shape because there is no net movement of water

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hypotonic solution

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a solution that has a lower concentraition of solute outside than inside the cell, causing water to flow into the cells by osmosis

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hypertonic solution

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a solution that has a higher concentration of solute outside than inside a cell, causing water to leae the cell by osmosis

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active transport

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energy-requiring process by which substances move across the plasma membrane against a concentration gradient

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endocytosis

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energy-requiring process by which large substances from the outside environment can enter a cell

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exocytosis

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energy-requiring process by which a cell expels wastes and secretes substances at the plasma membrane

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energy

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ability to do work

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thermodynamics

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study of the flow and transformation of energy in the universe

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metabolism

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all of the chemical reactions that occur within an organism

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photosynthesis

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two phase anabolic pathway in which the sun's light energy is converted to chemical energy for use by the cell

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cellular respiration

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catabolic pathway in which organic molecules are broken down to release energy for use by the cell

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adenosine triphosphate (ATP)

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ATP; energy carrying biological molecule, which when broken down, drives cellular activities

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thylakoid

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in chloroplasts, one of the stacked, flattened, pigment-containing membranes in which light dependent reactions occur

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granum

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one of the stacks of thylakoids in a plant's cholorplasts

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stroma

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fluid-filled space outside the grana in which light-dependent reactions take place.

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pigment

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light-absorbing colored molecule, such as chlorophyll and cartenoid, in the thylakoid membranes of chloroplasts

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NADP+

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in photosynthesis, the major electron carrier involved in electron transport

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Calvin Cycle

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light- independent reactions during phase 2 of photosynthesis in which energy is stored in organic molecules as glucose

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rubisco

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enzyme that converts inorganic carbon dioxide molecules into organic molecules during the final step of the Calvin Cycle

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anaerobic process

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metabolic process that does not require oxygen

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aerobic process

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a metabolic process that requires oxygen

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glycolysis

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anaerobic process; first stage of cellular respiration in which glucose is broken down into two molecules of pruvate

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Krebs cycle

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series of reactions in which pyruvate is broken down into carbon dioxide inside the mitochondria of cells; also called the tricarboxylic acid cycle and the citirc acid cycle

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fermentation

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process in which NAD+ is regenerated, allowing cells to maintain glycolysis in the absence of oxygen.

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cell cycle

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process of cellular reproduction, occuring in three main stages - interphase (growth), mitosis (nuclear division), and cytokinesis (cytoplasm division)

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interphase

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first stage of the cell cycle, during which a cell grows, matures, and replicates ins DNA

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mitosis

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second main stage of the cell cycle during which the cell's replicated DNA dicides and two genetically identical diploid daughter cells are produced

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cytokinesis

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third main stage of the cell cycle, during which the cell's cytoplasm divides, creating a new cell

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chromosome

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DNA containing structure that carries genetic material from one generation to another.

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chromatin

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relaxed from of DNA in the nucleus of a cell

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prophase

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first stage of mitosis, during which the cell's chromatin condenses into chromosomes.

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sister chromatid

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structure that contains identical DNA copies and is formed during DNA replication

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centromere

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cell structure that joins two sister chromatids

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spindle apparatus

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structure made of spindle fibers,centrioles, and aster fibers that is invovled in moving and organizing chromosomes before the cell divides

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metaphase

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second stage of mitosis in which motor proteins pull sister chromatids to the cell's equator

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anaphase

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third stage of mitosis in which sister chromatids are pulled apart and microtubules, along with motor proteins, move the chromosomes to opposite poles of the cell

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telophase

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last stage of mitosis in which nucleoli reappear. two new nuclear membranes begin to form, but the cell has not yet completely divided.

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cyclin

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one of the specific proteins that regulate the cell cycle

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cyclin-dependent kinase

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enzyme to which cyclin binds during interphase and mitosis, triggering and controlling activites during the cell cycle.

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cancer

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uncontrolled growth and division of cells that can be caused by changes in control of the cell cycle and also may be caused by environmental factors.

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carcinogen

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cancer-causing substance

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apoptosis

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programmed cell death

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stem cell

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unspecialized cell that can develop into a specialized cell under the right conditions.

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gene

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functional unit that controls inherited trait expression that is passed on from one generation to another generation

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homologous chromosome

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one of two paired chromosomes, one from each parent, that carries genes for a specific trait at the same location

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gamete

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a haploid sex cell, formed during meiosis, that can combine with another haploid sex cell and produce a diploid fertilized egg.

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haploid

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cell with half the number of chromosomes (n) as a diploid (2n) cell.

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fertilization

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process by which haploid gametes combine, forming a diploid cell with 2n chromosomes, with n chromosomes from the female parent and n chromosomes from the male parent

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diploid

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having two copies of each chromosomes

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meiosis

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reduction division process, occuring only in reproductive cells, in which one diploid (2n) cell produces four haploid (n) cells that are not genetically identical

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crossing over

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exchange of chromosomal segments between a pair of homologous chromosomes during prophase I of meiosis

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genetics

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science of heredity

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allele

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alternative form that a single gene may have for a particular trait

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dominant

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Mendel's name for a specific trait that appeared in the F1 generation

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recessive

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Mendel's name for a specific trait hidden or masked in the F1 generation

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homozygous

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organism with two of the same alleles for a specific trait

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heterozygous

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organism with two different alleles for a specific trait

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genotype

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an organism's allele pairs

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phenotype

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observable characteristic that is expressed as a result of an allele pair

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law of segregation

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Mendelian law stating that two alleles for each trait separate during meiosis

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hybrid

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organism heterozygous for a specific trait

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law of independent assortment

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Mendelian law stating that a random distribution of alleles occurs during the formation of gametes

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genetic recombination

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new combination of genes produced by crossing over and independent assortment

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polyploidy

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having one or more extra sets of all chromosomes, which, in polyploid plants, can often result in greater size and better growth and survival

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carrier

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individual heterozygous for a recesive disorder such as cystic fibrosis or Tay-Sachs disease

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pedigree

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diagrammed family history that is used to study inheritance patterns of a trait through several generations and that can be used to predict disorders in future offspring

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incomplete dominance

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complex inheritance pattern in which the heterozygous phenotype is intermediate between those of the two homozygous parent organisms

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codominance

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complex inheritance pattern that occurs when neither allel is dominant and both alleles are expressed

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multiple alleles

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having more than two alleles for a specific trait

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epistasis

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interaction between alleles in which one allele hides the effects of another allele

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sex chromosome

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X or Y chromosome; paired sex chromosomes determine an individual's gender - XX individuals are female and XY individuals are male

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autosome

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chromosome that is not a sex chromosome

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sex-linked trait

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characteristic, such as red-green color blindness, controlled by genes on the X chromosome; also called an X-linked trait

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polygenic trait

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characteristic, such as eye color or skin color, that results from the interaction of multiple gene pairs

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double helix

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twisted-ladder shape of DNA, formed by two nucleotide strands twisted around each other

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nucleosome

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repeating subunit of chromatin fibers, consisting of DNA coiled around histones

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semiconservative replication

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method of DNA replication in which parental strands separate, act as templates, and produce molecules of DNA with one parental DNA strand and one new DNA strand

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DNA polymerase

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enzyme that catalyzes synthesis of new DNA molecules

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Okazaki fragment

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short segment of DNA synthesized discontinuously in small segments in the 3' to 5' direction by DNA polymerase

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RNA

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ribonucleic acid; guides protein synthesis

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mRNA

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messenger RNA; type of RNA that carries genetic info from DNA in the nucleus to direct protein synthesis in the cytoplasm

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rRNA

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Ribosomal RNA; associates with proteins to form ribosomes

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tRNA

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transfer RNA; transports amino acids to the ribsome

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transcription

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process in which mRNA is synthesized from the template DNA

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RNA polymerase

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enzyme that regulates RNA synthesis

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intron

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in RNA processing, the intervenign coding sequence missing from the final mRNA

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exon

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in RNA processing, the coding sequence that remains in the final mRNA

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codon

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three based code in DNA or RNA

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translation

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process in which mRNA attaches to the ribosome and a protein is assembled

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mutation

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permanent change in a cell's DNA, ranging from changes