All Honors Bio Terms
Terms
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- chloroplast
- organelle found in some plant cells and certain unicellular organisms where photosynthesis takes place
- product
- material created as a result of a chemical reaction
- autotroph
- organism that makes its own food
- proton
- subatomic particle with a single unit of positive electric charge (+)
- cell cycle
- sequence of events from the production of a eukaryotic cell to the time the cell itself reproduces
- tumor suppressor gene
- gene that codes for a protein that stops cell division in particular situations
- atomic number
- number of protons in an atom's nucleus; is unique for each element
- tRNA
- RNA that translates the three-letter codons of mRNA to amino acids
- cancer
- disease caused by severe disruption of the mechanisms that normally control the cell cycle
- disaccharide
- sugar containing two monosaccharides
- amino acid
- monomer that makes up proteins; contains carboxyl and amino functional groups
- kinetic energy
- energy of motion
- neutron
- subatomic particle that has no charge (is electrically neutral)
- growth factor
- protein that initiates cell division
- fertilization
- the fusion of the nucleus of a haploid sperm cell and the nucleus of a haploid egg cell, forming a diploid zygote
- solution
- uniform mixture of two or more substances
- virus
- package of nucleic acid wrapped in a protein coat that must use a host cell's machinery to reproduce itself
- lipid
- one of a class of water-avoiding compounds
- sex chromosome
- one of two chromosomes of the 23rd pair of human chromosomes, which determine an individual's gender
- centrosome
- region of cytoplasmic material that in animal cells contains structures called centrioles
- recessive
- descriptive of an allele in a heterozygous individual that does not appear to affect a trait
- ionic bond
- chemical bond that occurs when an atom transfers an electron to another atom
- karyotype
- display of a person's 46 chromosomes
- Trisomy 21
- condition in which an individual has three number 21 chromosomes, resulting in Down syndrome
- osmosis
- passive transport of water across a selectively permeable membrane
- spindle
- framework of microtubules that guide the movement of chromosomes during mitosis and meiosis
- cell theory
- generalization that all living things are composed of cells, and that cells are the basic unit of structure/function in living things
- down syndrome
- general set of symptoms in people with trisomy 21
- zygote
- diploid cell formed when the nucleus of a haploid sperm cell fuses with the nucleus of a haploid egg cell
- selectively permeable membrane
- membrane that allows some substances to pass more easily than others and blocks the passage of some substances altogether
- potential energy
- energy stored due to an object's position or arrangement
- cytoplasm
- region of a cell between the nucleus and the plasma membrane
- cellular respiration
- chemical process that uses oxygen to convert chemical energy stored in organic molecules into ATP (adenosine triphosphate)
- Calvin cycle
- cycle in plants that makes sugar from carbon dioxide, H+ ions, and high-energy electrons carried by NADPH
- diploid
- having two homologous sets of chromosomes
- chlorophyll
- pigment that gives a chloroplast its green color; uses light energy to split water molecules during photosynthesis
- adhesion
- attraction between unlike molecules
- hydrophobic
- avoids water molecules
- monohybrid cross
- mating of two organisms that differ in only one character
- data
- recorded observations or items of information
- starch
- polysaccharide in plant cells that consists entirely of glucose monomers
- cytokinesis
- process by which the cytoplasm of a cell is divided in two; usually follows mitosis and meiosis
- aqueous solution
- solution in which water is the solvent
- flagella
- long, thin, whip-like structures, with a core of microtubules, that enable some cells to move
- mitotic phase
- stage of the cell cycle when a cell is actively dividing
- genetic counselor
- person trained to collect, analyze, and explain data about human inheritance patterns
- domain
- broadest category used to classify life forms
- carbon cycle
- process by which carbon moves from inorganic to organic compounds and back
- ion
- atom that has become electrically charged as a result of gaining or losing an electron
- eukaryotic cell
- cell with a nucleus (surrounded by its own membrane) and other internal organelles
- glycolisis
- the splitting in half of a glucose molecule; the first stage of cellular respiration and fermentation
- dihybrid characters
- mating of two organisms that differ in two characters
- hypertonic
- having a higher concentration of solute than another solution
- reactant
- starting material for a chemical reaction
- genetic recombination
- new combination of genetic information in a gamete as a result of crossing over during prophase I of meiosis
- prokaryotic cells
- cell lacking a nucleus and most other organelles
- nitrogenous base
- single or double ring of carbon and nitrogen atoms with attached functional groups, found in nucleic acids
- golgi apparatus
- cellular organelle that modifies, stores, and routes cell products
- greenhouse effect
- process by which atmospheric gases trap heat close to Earth's surface and prevent it from escaping into space
- organic molecule
- carbon-based molecule
- radioactive isotope
- isotope in which the nucleus decays (breaks down) over time, giving off radiation in the form of matter and energy
- inorganic molecule
- non-carbon-based molecule
- light reactions
- chemical reactions that convert the sun's energy to chemical energy; take place in the membranes of thylakoids in the chloroplast
- theory
- well-tested explanation that makes sense of a great variety of scientific observations
- active transport
- movement of molecules across a membrane requiring energy to be expended by the cell
- monomer
- small molecular unit that is the building block of a larger molecule
- oncogene
- cancer-causing gene
- benign tumor
- mass of cells that remain at their original site
- chloroplast
- organelle found in some plant cells and certain unicellular organisms where photosynthesis takes place
- enzyme
- specialized protein that catalyzes the chemical reactions of a cell
- organelle
- part of a cell with a specific function
- genetics
- study of heredity
- histone
- small protein that DNA wraps around
- rRNA
- RNA component of ribosomes
- functional group
- group of atoms within a molecule that interacts in predictable ways with other molecules
- purine
- double-ring nitrogenous base
- chromosome theory of inheritance
- generalization that genes are located on chromosomes and that the behavior of chromosomes during meiosis and fertilization accounts for inheritance patterns
- saturated fat
- fat in which all three fatty acid chains contain the maximum possible number of hydrogen atoms
- cohesion
- tendency of molecules of the same kind to stick to one another
- ATP
- (adenosine triphosphate) main energy source that cells use for most of their work
- DNA polymerase
- enzyme that makes the covalent bonds between the nucleotides of new DNA strands
- homozygous
- having identical alleles for a gene
- anaerobic
- without oxygen
- hybrid
- offspring of two different true-breeding varieties
- steroid
- lipid molecule with four fused carbon rings
- gene
- unit of inherited information in DNA
- stroma
- thick fluid contained in the inner membrane of a chloroplast
- translation
- process by which a sequence of nucleic acids in RNA is used to direct the production of a chain of specific amino acids
- centromere
- region where two sister chromatids are joined tightly together
- adaption
- inherited characteristic that improves an organism's ability to survive and reproduce in a particular environment
- mutagen
- physical or chemical agent that causes mutations
- micrograph
- photograph of the view through a microscope
- phenotype
- observable traits of an organism
- double helix
- two strands of nucleotides wound about each other; structure of DNA
- ATP synthase
- protein structure in cell mitochondria that uses energy from H+ ions to convert ADP to ATP
- genome
- complete set of an organism's genetic material
- denaturation
- loss of normal shape of a protein due to heat or other factor
- intermediate inheritance
- inheritance in which heterozygotes have a phenotype intermediate between the phenotypes of the two homozygotes
- carrier
- individual who has one copy of the allele for a recessive disorder and does not exhibit symptoms
- aerobic
- requiring oxygen
- sex-linked gene
- located on a sex chromosome
- catalyst
- agent that speeds up chemical reactions
- nucleolus
- ball-like mass of fibers and granules in a cell nucleus
- hydrocarbon
- organic molecule composed of only carbon and hydrogen atoms
- plasma membrane
- thin outer boundary of a cell that regulates the traffic of chemicals between the cell and its surroundings
- homeostasis
- internal stability or "steady state" maintained by the body
- Punnet square
- diagram showing the probabilities of the possible outcomes of a genetic cross
- fat
- organic compound consisting of a three-carbon backbone (glycerol) attached to three fatty acids
- phospolipid bilayer
- two-layer "sandwich" of molecules that surrounds a cell
- species
- distinct form of life
- RNA splicing
- process by which the introns are removed from RNA transcripts and the remaining exons are joined together
- allele
- alternative form of a gene
- genotype
- genetic makeup of an organism; an organism's combination of alleles
- telophase
- final stage of mitosis and of meiosis I and II, in which the chromosomes reach the spindle poles, nuclear envelopes form around each set of daughter chromosomes, and the nucleoli reappear
- interphase
- stage of the cell cycle during which a cell carries out its metabolic processes and performs its functions in the body
- monosaccharide
- sugar containing one sugar unit
- haploid
- having a single set of chromosomes
- organism
- living thing
- electron
- subatomic particle with a single unit of negative electric charge (-)
- molecule
- two or more atoms held together by covalent bonds
- meiosis
- type of cell division that produces four cells, each with half as many chromosomes as the parent cell
- nucleotide
- building block (monomer) of nucleic acid polymers
- temperature
- measure of the average energy of random motion of particles in a substance
- sexual reproduction
- process in which genetic material from two parents combines and produces offspring that differ genetically from either parent
- mitochondria
- cellular organelles where cellular respiration occurs
- buffer
- maintains a fairly constant pH in a solution by accepting H+ ions when their levels rise and donating H+ ions when their levels fall
- equilibrium
- point at which the number of diffusing molecules moving in one direction is equal to the number moving in the opposite direction
- active site
- region of an enzyme into which a particular substrate fits
- metaphase
- second stage of mitosis and of meiosis I and II when the spindle is fully formed and all of the chromosomes are held in place
- polypeptide
- chain of linked amino acids
- nucleus
- in an atom, the central core that contains protons and neutrons, houses the cell's genetic material in the form of DNA
- DNA replication
- process of copying DNA molecules
- fermentation
- cellular process of making ATP without oxygen
- lysosome
- membrane-bound sac containing digestive enzymes that can break down proteins, nucleic acids, and polysaccharides
- metastasis
- spread of cancer cells beyond their original site in the body
- exocytosis
- process of exporting proteins from a cell by a vesicle fusing with the plasma membrane and spilling the proteins outside the cell
- compound
- substance containing two or more elements chemically combined in a fixed ratio
- polgenic inheritance
- combined effect of two or more genes on a single character
- mRNA
- RNA molecule transcribed from a DNA template
- polar molecule
- molecule in which opposite ends have opposite electric charges
- pedigree
- family tree that records and traces the occurrence of a trait in a family
- biosphere
- all the parts of the planet that are inhabited by living things; sum of all Earth's ecosystems
- gene locus
- specific location of a gene on a chromosome
- anticodon
- in tRNA, a triplet of nitrogenous bases that is complementary to a specific codon in mRNA
- mutation
- any change in the nucleotide sequence of DNA
- natural selection
- process by which individuals with inherited characteristics well-suited to the environment leave more offspring than do other individuals
- system
- complex organization formed from a simpler combination of parts
- RNA
- nucleic acid containing the sugar ribose
- inference
- logical conclusion based on observations
- ph scale
- a range of numbers used to describe how acidic or basic a solution is; ranges from 0 (most acidic) to 14 (most basic)
- chemical energy
- potential to perform work due to the arrangement of atoms within molecules
- element
- pure substance that cannot be broken down into other substances by chemical or physical means
- isotope
- one of several forms of an element, each containing the same number of protons in their atoms but a different number of neutrons
- microtubule
- straight, hollow tube of proteins that gives rigidity, shape, and organization to a cell
- consumer
- organism that obtains food by eating producers (autotrophs) or other consumers
- trace element
- element critical to health that makes up less than 0.01 percent of body mass
- Krebs cycle
- stage of cellular respiration that finishes the breakdown of pyruvic acid molecules to carbon dioxide, releasing energy
- heterotroph
- organism that obtains food by eating other organisms
- transposon
- genetic element that moves from one location to another in a genome
- glycogen
- polysaccharide in animal cells that consists of many glucose monomers
- trait
- variation of a particular inherited character
- chromosome
- condensed threads of genetic material formed from chromatin as a cell prepares to divide
- multicellular
- consisting of many cells
- duplication
- change to a chromosome in which part of the chromosome is repeated
- hydrophillic
- attracts water molecules
- passive transport
- diffusion across a membrane requiring only the random motion of molecules with no energy expended by the cell
- hypothesis
- suggested, testable answer to a well-defined scientific question
- translocation
- change to a chromosome in which a fragment of one chromosome attaches to a nonhomologous chromosome
- asexual reproduction
- process in which a single cell or set of cells produces offspring that inherit all their genetic material from one parent
- metabolism
- all of a cell's chemical processes
- substrate
- specific reactant acted on by an enzyme
- endoplasmic reticulum
- network of membranes within a cell's cytoplasm that produces a variety of molecules
- calorie
- amount of energy required to raise the temperature of 1 g of water 1°C
- dominant
- descriptive of an allele in a heterozygous individual that appears to be the only one affecting a trait
- base
- compound that removes H+ ions from an aqueous solution and that measures more than 7 on the pH scale
- nuclear envelope
- double membrane that surrounds a cell nucleus
- intron
- internal noncoding region in RNA transcript
- prophase
- first stage of mitosis and of meiosis I and II, when the already replicated chromosomes condense
- malignant tumor
- mass of abnormal cells resulting from uncontrolled cancer cell division
- chromatin
- combination of DNA and protein molecules, in the form of long, thin fibers, making up the genetic material in the nucleus of a eukaryotic cell
- acid
- compound that donates H+ ions to an aqueous solution and measures less than 7 on the pH scale
- bacteriaphage
- virus that infects bacteria; also called a "phage"
- endocytosis
- process of taking material into a cell within vesicles that bud inward from the plasma membrane
- hydrogen bond
- bond created by the weak attraction of a slightly positive hydrogen atom to a slightly negative portion of another molecule
- unsaturated fats
- fat with less than the maximum number of hydrogens in one or more of its fatty acid chains
- pyrimidine
- single-ring nitrogenous base
- homologous chromosome
- one of a matching pair of chromosomes, one inherited from each parent
- solvent
- substance in a solution that dissolves the other substance and is present in the greater amount
- protein
- polymer constructed from a set of 20 amino acid monomers
- thermal energy
- total amount of energy associated with the random movement of atoms and molecules in a sample of matter
- carbohydrate
- organic compound made of sugar molecules
- nondisjunction
- event during meiosis in which homologous chromosomes or sister chromatids fail to separate
- mitosis
- process by which the nucleus and duplicated chromosomes of a cell divide and are evenly distributed, forming two daughter nuclei
- facilitated diffusion
- pathway provided by transport proteins that helps certain molecules pass through a membrane
- model
- physical, mental, or mathematical representation of how people understand a process or an idea
- cholesterol
- steroid molecule present in the plasma membranes of animal cells
- photosynthesis
- process by which plants use the sun's energy to convert water and carbon dioxide into sugars
- microfilament
- solid rod of protein, thinner than a microtubule, that enables a cell to move or change shape
- evolution
- generation-to-generation change in the proportion of different inherited genes
- variable
- any factor in an experiment that is not constant (any factor that can change)
- diffusion
- net movement of the particles of a substance from where they are more concentrated to where they are less concentrated
- cells
- basic unit of living matter; separated from its environment by a plasma membrane
- thermal energy
- total amount of energy associated with the random movement of atoms and molecules in a sample of matter
- crossing over
- exchange of genetic material between homologous chromosomes during prophase I of meiosis
- anaphase
- third phase of mitosis and of meiosis I and II, in which the sister chromatids separate and move toward the poles of the spindle
- generalization
- general conclusion
- solute
- substance in a solution that is dissolved and is present in a lesser amount
- producer
- organism that makes its own food (autotroph) and produces organic molecules
- controlled experiment
- experiment that tests the effect of a single variable
- test cross
- mating of an individual of unknown genotype but dominant phenotype with a homozygous recessive individual
- vesicle
- small membrane-bound sac that functions in moving products into, out of, and within a cell
- observation
- use of the senses to gather and record information about structures or processes in nature
- vacuole
- membrane-bound sac that buds from the endoplasmic reticulum or the Golgi apparatus
- inversion
- change to a chromosome in which a fragment of the original chromosome is reversed
- codominance
- inheritance pattern in which a heterozygote expresses the distinct traits of both alleles
- chemical reaction
- breaking of old and formation of new chemical bonds that result in new substances
- matter
- anything that occupies space and has mass
- polysaccharide
- long polymer chain made up of simple sugar monomers
- deletion
- change to a chromosome in which a fragment of the chromosome is removed
- cellulose
- polysaccharide consisting of glucose monomers that reinforces plant-cell walls
- ecosystem
- community of living things plus the nonliving features of the environment that support them
- transcription
- process by which a DNA template is used to produce a single-stranded RNA molecule
- exon
- coding region in RNA transcript
- thylakoid
- disk-shaped sac in the stroma of a chloroplast; site of the light reactions of photosynthesis
- RNA polymerase
- transcription enzyme that links RNA nucleotides together
- population
- group of individuals of the same species living in a particular area at the same time
- genetic linkage
- tendency for alleles of genes on the same chromosome to be inherited together
- cell plate
- disk containing cell wall material that develops in plant cells during cytokinesis, eventually dividing the cell into two daughter cells
- activation energy
- minimum amount of energy required to trigger a chemical reaction
- eukaryotic cells
- cell with a nucleus (surrounded by its own membrane) and other internal organelles
- isotonic
- having a solute concentration equal to that of another solution
- gamete
- egg or sperm sex cell that contains a single set of chromosomes, one from each homologous pair
- cilia
- short structures projecting from a cell and containing bundles of microtubules that move a cell through its surroundings
- hypotonic
- having a lower concentration of solute than another solution
- codon
- in RNA, a three-base "word" that codes for one amino acid
- prokaryotic cell
- cell lacking a nucleus and most other organelles
- tetrad
- group of four chromatids formed during prophase I of meiosis by the two sister chromatids in each of the two homologous chromosomes
- sister chromatid
- one of a pair of identical chromosomes created before a cell divides
- ribosome
- cluster of proteins and nucleic acids that constructs proteins in a cell
- DNA
- molecule responsible for inheritance; nucleic acid that contains the sugar deoxyribose
- heterozygous
- having different alleles for a gene
- covalent bond
- chemical bond that forms when two atoms share electrons
- polymer
- long chain of small molecular units (monomers)
- evidence
- collected body of data from observations and experiments
- unicellular
- consisting of a single cell
- cross-fertilization
- process by which sperm from one flower's pollen fertilizes the eggs in a flower of a different plant
- cell wall
- strong wall outside a plant cell's plasma membrane that protects the cell and maintains its shape
- atom
- smallest particle of an element