10th grade Biology Level 3 Vocabulary list:
Introduction to Biology:
Biology – the study of life
Organism – a living thing; anything that can carry out the processes of life
independently
Cell – a highly organized, tiny structure that is enclosed in a membrane
Multicellular organism – an organism with more than 1 cell
Specialized – has a certain job
Unicellular organism – an organism made of only 1 cell
Homeostasis – maintaining constant internal conditions regardless of external
changes
Metabolism – the sum of all chemical reactions carried out in an organism
Heterotrophs – organisms that consume food
Autotrophs – organisms that make their own food through the process of
photosynthesis
Responsiveness – living organisms react to their own environment
Reproduction – production of offspring
Heredity – the passing of traits from parent to offspring
Asexual reproduction – production of offspring that is identical to the 1 parent
Sexual reproduction – production of offspring that has a mix of traits from 2
parents
Growth – increasing in size or number of cells
Development – a change in form over the course of an organism’s life
Taxonomy – the study of the classification of organisms
Taxa – the categories into which organisms are grouped
Scientific method:
Observation – the act of perceiving or noting events using the senses
Direct observation – things we can see
Indirect observation – things that cannot be seen but must be observed based on
things we can see
Hypothesis – a possible explanation that can be tested by observation or
experimentation
Qualitative data – can be observed but not measured
Quantitative data – can be measured
Experiment – a procedure that is carried out under controlled conditions to test a
hypothesis
Control group – receives no experimental treatment
Independent variable – the single factor that scientists can change in an
experiment
Dependent variable – factors that may change as a result of the independent
variable
Belief – opinion or conviction that something is true
Fact – truth known by actual experience or evidence
Theory – a system of ideas that explains many related observations and is
supported by a large body of evidence acquired through scientific observation
Principle/law – truths that are valid everywhere in the universe
Biochemistry Part I
Matter – anything that has mass and takes up space
Atom – smallest unit of matter that cannot be broken down by chemical means
Isotope – atoms that differ in their number of neutrons
Molecule – a group of atoms held together by covalent bonds
Compound – bonded atoms of two or more different elements
Chemical formula – shows the kind and proportion of atoms
Structural formula – shows the arrangement of atoms within the molecule
Ion – atom that has a charge due to gaining or losing electrons
Ionic bond – the attractive force between two oppositely charged ions
Covalent bond – formed when atoms share electrons
Solution – a mixture in which ions or other molecules are evenly distributed in
another substance
Acid – compounds that increase the number of hydrogen/hydronium ions when
dissolved in water
Base – compounds that increase the number of hydroxide ions when dissolved in
water
pH – a measure of how acidic or basic a solution is
Buffer – a substance that can prevent changes in pH
Biochemistry Part II
Polar – molecules with partial charges on opposite ends
Hydrogen bond – Hydrogen ion on one molecule is attracted to a negatively
charged atom on an adjacent molecule
Cohesion – water is attracted to itself
Surface tension – cohesive forces cause water to act as though there is a thin “skin”
on the surface
Adhesion – water is attracted to something other than itself
Capillarity – adhesion and cohesion cause water to move upward through small
tubes against gravity
DNA Part I
Genes – the instructions for inherited traits
DNA replication – the process in which DNA makes an exact copy of itself prior to
cell division
DNA and protein synthesis Part II
mRNA – messenger RNA; a copy of the DNA code that can leave the nucleus and
deliver the instructions to make a protein to the ribosome
Ribosome – a part of the cell that makes proteins
rRNA – ribosomal RNA; makes up the ribosomes
tRNA – transfer RNA; brings amino acids to the ribosome to build proteins
Transcription – the process of making mRNA from DNA
Translation – the process of making a protein
Codon – a group of 3 nucleotides on an mRNA molecule; represents 1 amino acid
Anticodon – a group of 3 nucleotides on a tRNA molecule
Gene mutation – a change in the sequence of bases within a gene
Frameshift mutation – a base is added or removed in a gene
Point mutation – 1 base is substituted for another in a gene
Cell growth and reproduction
Chromatin – DNA and protein seen in a non-dividing cell
Chromosomes – DNA and protein in a dividing cell; formed when chromatin coils
Histones – proteins that help to coil the DNA
Chromatids – the two identical halves of a replicated chromosome
Centromere – holds the sister chromatids together on a replicated chromosome
Interphase – time in-between cell divisions
G1 phase – part of interphase during which the cell grows and performs most
activities
S phase – the part of interphase during which DNA replication occurs
G2 phase – the part of interphase during which the cell grows and prepares for cell
division
G0 phase – exiting the cell cycle; cells that never divide again remain in this stage
M phase – mitosis; the stage during which cell division occurs
Mitosis – the process of dividing the DNA between 2 new cells
Cytokinesis – the process of splitting the cytoplasm between 2 new cells
Prophase – first phase of mitosis; nuclear membrane and nucleolus disappear;
spindle fibers form; chromosomes become visible and attach to spindle fibers
Metaphase – second phase of mitosis; chromosomes line up at the middle of the cell
Anaphase – third phase of mitosis; sister chromatids separate and become
daughter chromosomes
Telophase – the last phase of mitosis; cell divides; nuclear membrane and nucleolus
reappear; spindle fibers disappear; chromosomes turn back into chromatin
Spindle fibers – help chromosomes to divide during mitosis
Nuclear membrane – surrounds the nucleus; disappears during cell division
Nucleolus – found within the nucleus and disappears during cell division
Binary fission – process of cell division used by bacteria
Meiosis and sexual reproduction
Sexual reproduction – offspring are produced from a union of egg and sperm;
offspring are different from parents
Asexual reproduction – offspring are produced from one parent; offspring are
identical to the parent
Gamete – a sex cell; eggs and sperm
Egg – female sex cell
Sperm – male sex cell
Zygote – a fertilized egg; formed when a sperm cell fertilizes an egg cell
Fertilization – occurs when a sperm cell fuses with an egg cell
Fragmentation – body breaks into several parts; each part grows into a new
organism; a form of asexual reproduction
Budding – new individuals break off from existing ones; a form of asexual
reproduction
Binary fission – a process of cell division used by bacteria
Parthenogenesis – a female makes a viable egg that grows into an adult without
being fertilized by a sperm cell
Somatic cells – body cells that do not participate in sexual reproduction
Germ cells – cells specialized for sexual reproduction, such as eggs and sperm
Karyotype – a picture of the chromosomes
Homologous chromosomes – chromosomes with the same genes
Sex chromosomes – chromosomes that determine gender
Autosomes – chromosomes that have nothing to do with determining gender
Diploid – a cell that has two chromosomes from each homologous pair
Haploid – a cell that has one chromosome from each homologous pair
Meiosis – a process of cell division that makes eggs and sperm; reduces the
chromosome number by half
Crossing over – chromosomes exchange genetic material
Trisomy – having three copies of one chromosome instead of two
Monosomy – having only one copy of a chromosome instead of two
Deletion – when a section of a chromosome is missing
Duplication – when a section of a chromosome is repeated
Translocation – when two non-homologous chromosomes exchange information
Inversion – when a section of chromosome is backwards
Spermatogenesis – meiosis in males; makes sperm
Oogenesis – meiosis in females; makes eggs
Polar bodies – cells formed during meiosis in females that die, but provide a place
to discard extra chromosomes
Mendel and Heredity
Heredity – the passing of traits from parent to offspring
Genetics – the study of heredity
Genes – sections of DNA that determine a person’s traits
Dominant – takes over the recessive form of a gene
Recessive – only shown when two recessive genes are present
Alleles – versions of a trait
Segregation – pairs of alleles are separated during meiosis
Gamete – egg or sperm cell; sex cell
Haploid – cell that has one chromosome from each homologous pair
Diploid – cell that has two chromosomes from each homologous pair
Independent assortment – during gamete formation, alleles separate
independently of one another so long as they are on different chromosomes
Linked genes – genes found on the same chromosome which are inherited together
Genotype – the gene a person inherits
Homozygous dominant – an individual inherits two dominant alleles
Homozygous recessive – an individual inherits two recessive alleles
Heterozygous – an individual inherits a dominant and a recessive allele
Phenotype – the appearance of an individual
Monohybrid cross – a cross involving 1 trait
Punnett squares – a chart to show inheritance
Probability – the odds of an event occurring
Dihybrid cross – a cross involving two traits
Codominance – when both alleles are fully expressed in an individual who is
heterozygous; example AB blood type
Incomplete dominance – when a heterozygous individual show a phenotype that is
an intermediate form of the homozygous forms; ex: red x white = pink plants
Sex-linked traits – traits that are carried on the X or Y chromosome
Sex-influenced traits – traits that are affected by gender and expressed differently
in males and females; baldness in males
Evolution Part I
Evolution – change in organisms over time
Darwin – came up with theory to explain how species change over time
Lyell – geologist who suggested earth changed due to geologic forces
Malthus – suggested overpopulation would limit the human population size
Lamarck – explained the long neck of the giraffe due to them stretching their necks
Wallace – came up with a similar theory to Darwin’s
Artificial selection – humans breed organisms for desired traits
Natural selection – organisms with traits best suited to the environment survive
and pass on their genes to the next generation
Fitness – reproductive success
Overproduction – more organisms are produced than can survive in the
environment
Variation – differences in organisms
Selection – some organisms have variations that make them better suited to an
environment
Adaptation – organisms with traits better suited to the environment pass on their
traits more frequently than others
Stabilizing selection – the average phenotype is selected in an environment
Directional selection – one extreme phenotype is selected in an environment
Disruptive selection – 2 or more phenotypes are selected in the same environment
Variations - differences in a population that play no role in fitness
Adaptations – traits that all in a population have because they improve fitness
Evolution – part II
Fossils – remnants of past life
Biogeography – distribution of plants and animals around the world
Developmental biology – studying embryos
Homologous structures – structures that develop from similar tissue but may not
serve the same purpose
Analogous structures – structures that serve the same purpose, but evolved
independently of each other
Vestigial structures – structures that serve no purpose in the present day
organism, but may have been used in the past
Biochemistry – DNA, proteins, amino acids shared among organisms
Gene pool – all of the collective genes in a population
Microevolution – changes in the allele frequencies of a population that do not lead
to a new species
Macroevolution – changes in populations that lead to the development of new
species
Speciation – development of a new species
Species – groups of organisms that can interbreed and share a gene pool
Reproductive isolation – organisms can no longer interbreed with one another
Pre-mating reproductive isolation – mating is not attempted
Post-mating reproductive isolation – organisms mate, but offspring is not viable
or fertile
Hybrids – created by crossing two different species together
Natural selection – organisms with the traits best suited to the environment
survive and pass the genes for those successful traits onto their offspring
Migration – movement of organisms from one environment to another
Mate choice – organisms select a mate based on certain criteria
Mutation – changes in DNA code
Genetic drift – allele frequencies change due to chance alone
Founder effect – only a fraction of the gene pool is represented when a small
subgroup breaks away from the main population
Extinction – an entire species dies out
Convergent evolution – unrelated species evolve similar traits as they adapt to the
same environments
Divergent evolution – 2 or more organisms become different as they adapt to
different environments
Adaptive radiation – a few migrate to a new area, then change as they adapt to a
new environment
Gradualism – change is slow and steady
Punctuated equilibrium – period of no change followed by rapid speciation
Coevolution – organisms change in close association with one another, like
predator and prey
Human evolution – not on Keystone exam
Cell structure
Magnification – increase in the apparent size of an organism
Resolving power – the distance needed to distinguish two objects as separate
Compound light microscope – uses light and glass lenses to look at living
specimens
Scanning electron microscope – beam of electrons bounces off of specimen to
produce 3D image
Transmission electron microscope – beam of electrons passes through a
specimen to produce a flat image
Organelles – structures that carry out specific functions inside a cell
Eukaryotic cells – cells that have a nucleus and organelles
Prokaryotic cells – cells lacking a nucleus and organelles
Cell membrane (plasma membrane) – surrounds a cell and controls what enters
and leaves a cell
Cell wall – found in plant cells for additional support
Cytoplasm – the area in a cell between the nucleus and cell membrane
Cytosol – the fluid in the cytoplasm that surrounds the organelles
Nucleus – controls all cell activities
Chromatin – DNA and protein found in the nucleus of a cell
Nucleolus – found in the nucleus; makes ribosomal RNA
Nuclear membrane – surrounds the nucleus
Nuclear pores – openings in the nuclear membrane that allow ribosomal RNA to
leave and proteins to enter the nucleus
Ribosomes – make proteins
Rough ER – has ribosomes; aids in protein synthesis
Smooth ER – lacks ribosomes; packages proteins and sends them to the golgi
apparatus
Golgi apparatus – modifies, sorts, and packages proteins for distribution
Vacuoles – store materials in a cell
Lysosomes – digests materials in a cell
Chloroplasts – site of photosynthesis; makes glucose; only in plants
Mitochondria – site of cellular respiration; makes ATP/energy
Cytoskeleton – gives the cell shape and support/helps move materials around the
cell
Centrioles – only in animal cells; help with cell division
Cilia – help with movement; small and numerous
Flagella – help with movement; long and singular
Unicellular organisms – contain only 1 cell
Multicellular organisms – contain more than 1 cell
Specialized – have certain jobs
Colonial organisms – cells live connected as a group, but do not depend on one
another for survival
Tissue – distinct group of cells that have similar structure and functions
Organs – a collection of tissues that carry out a specific function in the body
Organ systems – made up of various organs that carry out a major body function
Cells and their environment
Cell membrane – surrounds the cell and controls what enters and leaves the cell
Phospholipid bilayer – two layers of phospholipids that make up the cell
membrane
Fluid mosaic model – model used to describe the structure of the plasma
membrane
Polar head – water-loving end of a phospholipid
Nonpolar tail – water-fearing end of a phospholipid
Carbohydrate – allow cells to communicate with one another
Cholesterol – strengthens the plasma membrane
Proteins – allow large particles to cross the plasma membrane
Selectively permeable – allows only certain materials to cross the membrane
Passive transport – requires no cell energy, moving materials from high to low
concentration
Active transport – requires cell energy moving materials against their
concentration gradient from low to high concentration
Concentration gradient – a difference in concentration from one area to another
Diffusion – the movement of molecules from high to low concentration
Osmosis – the diffusion of water
Facilitated diffusion – using proteins to move materials from high to low
concentration
Equilibrium – a state in which all materials are evenly concentrated
Turgor pressure – makes plant rigid due to a high amount of water in the cell
Exocytosis – vesicles expel materials from the cell by fusing the vesicle to the cell
membrane
Endocytosis – cell membrane wraps around a material forming a vesicle to bring
the material into the cell
Vesicles – tiny storage units
Phagocytosis – form of endocytosis in which large particles are brought into a cell
Pinocytosis – form of endocytosis in which small particles or liquids are brought
into a cell
Receptor-mediated endocytosis – form of endocytosis in which specific molecules
are brought into a cell
Enzymes and cell respiration
Enzyme – speeds up the rate of a chemical reaction
Substrate - molecule that reacts with enzyme
Active site – region on an enzyme where a substrate attaches
Energy of activation – the minimum amount of energy needed to start a reaction
Induced fit model – a model used to describe enzyme function where the active site
of the enzyme undergoes a slight change to fit with the substrate
Denature – when an enzyme changes shape due to changes in temperature or pH
Aerobic – with oxygen
Anaerobic – without oxygen
Cellular respiration – the process of making ATP from glucose and oxygen; gives
off carbon dioxide and water in the process
Glucose – the sugar that is converted into ATP
Oxygen – a gas that helps convert glucose into ATP
ATP - energy
Water – a byproduct of cellular respiration
Carbon dioxide – a byproduct of cellular respiration
Glycolysis – the 1st phase of cellular respiration; makes ATP and NADH
Transition reaction – the 2nd phase of aerobic cellular respiration; makes NADH
and CO2
Citric acid cycle – the 3rd phase of aerobic cellular respiration; makes ATP, CO2,
NADH, and FADH2
Electron transport system – the final phase of aerobic cellular respiration; makes
ATP and water
ATP – made of ADP + P; breaks down into ADP + P
ADP – ADP + P – join to make ATP
NAD+ - accepts H+ to become NADH
NADH – loses H+ to become NAD+
FAD – accepts H+ to become FADH2
FADH2 – loses H+ to become FAD
Mitochondria – location of cellular respiration
Cristae – folds in the mitochondria; location of the electron transport system
Matrix – fluid in the mitochondria; location of the transition reaction and the citric
acid cycle
Fermentation – follows glycolysis when no oxygen is available
Photosynthesis
Producers – organisms that make their own food through photosynthesis
Consumers – organisms that eat other organisms for food
Carbon dioxide – reduced to glucose during photosynthesis
Water – split to produce oxygen during photosynthesis
Glucose – end product of photosynthesis
Oxygen – end product of photosynthesis
Chloroplasts – site of photosynthesis
Mesophyll cells – contain chloroplasts in a leaf
Stomata – pores in a leaf to allow carbon dioxide in and oxygen out
Stroma – fluid inside of a chloroplast
Thylakoid – discs inside of chloroplast
Grana – stacks of thylakoids inside of chloroplast
Chlorophyll – the pigment in leaves that makes leaves appear green in the spring
and summer
Oxidation – loss of electrons
Reduction – gain of electrons
Light-dependent reactions – first set of reactions in photosynthesis which require
the sun
Light-independent reactions – second set of reactions in photosynthesis which do
not require the sun
Photosystem II – first step of light-dependent reactions; contain electrons that are
energized when hit by the sun
Photosystem I – electrons travel here after going through an electron transport
system and are energized by the sun
Calvin Cycle – the light-independent reactions that reduce carbon dioxide to
glucose
NADP+ - reduced to NADPH during the light-dependent reactions of photosynthesis
NADPH – produced when NADP+ accepts hydrogen ions
ATP – formed from ADP + P
ADP – accepts P to form ATP
Ecology
Ecosystem – a community of organisms and their abiotic components
Biotic – living components of an ecosystem
Abiotic – nonliving components of an ecosystem
Autotrophs – organisms that make their own food
Heterotrophs – organisms that consume other organisms for food
Herbivores – organisms that feed on plants
Carnivores – organisms that feed on meat
Omnivores – organisms that feed on plants and meat
Decomposers – organisms that break down dead organic waste
Primary consumer – organism that gets its energy from plants
Secondary consumer – organism that gets its energy from primary consumers
Tertiary consumer – carnivores that eat other carnivores
Food chain – a diagram that links organisms together by who eats whom
Food web – interconnected food chains
Predation – interaction between two organisms in which one kills and eats the
other
Parasitism – interaction between two organisms in which one benefits while the
other is harmed
Symbiosis – a relationship in which two species live in close association with one
another
Commensalism – a symbiotic relationship in which one species benefits while the
other is neither helped nor harmed
Mutualism – a symbiotic relationship in which both species benefit
Limiting factors – factors that can affect the size of a population
Biotechnology
DNA fingerprinting – involves separating the noncoding sequences of DNA using
gel electrophoresis in order to observe the banding patterns that are unique to
every individual
Gel electrophoresis – an electric current is used to separate DNA fragments
according to size
Stem cell research – study of how stem cells (cells that can become any type of
tissue) can be used to treat various conditions
Cloning – making an exact copy of an existing organism
Gene therapy – a technique to correct mutated genes that cause disease
Human genome project – a project that mapped the sequence of DNA in humans
and identified all human genes
Genetic engineering – manipulating the DNA of one organism in order to insert the
DNA of another organism