9th Grade Biology Midterm
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210 terms
Terms | Definitions |
|---|---|
 biosphere | all living things and the places they are found |
| biodiversity | variety of life across the biosphere |
| species | specific type of organisms |
| biology | scientific study of all forms of life |
| organism | any individual living thing |
| cell | basic unit of life |
| metabolism | chemical process that builds up and breaks down materials |
| DNA | genetic material |
| system | organized group of related parts that work together |
| ecosystem | physical environment wirh different interacting species |
| homeostasis | maintenance of internal conditions in organisms |
| evolution | change in living things over time |
| adaptation | inherited trait that gives an adavantage to a species |
| observation | using tools to study the world |
| data | recorded observations |
| hypothesis | proposed answer to a scientific question |
| experiments | process of studying factors to find causes and effects |
| independant variable | factor that is changed in experiments |
| dependant variable | factor that is observed in experiments |
| constant | factors that stay the same in experiments |
| theory | proposed explanation for observations that is supported by evidence |
| microscope | tool that provides enlarged images of an object |
| gene | segment of DNA |
| molecular genetics | study and manipulation of DNA |
| genomics | study and comparison of genomes |
| biotechnology | application of living things and biological processes |
| transgenic | organisms that alter or have more than one species' genes |
| atom | smallest unit of matter |
| element | particular type of atom |
| compound | substance made of different elements in a specific ratio |
| ion | atom that has lost or gained an electron |
| ionic bond | bond between oppositely charged ions |
| covalent bond | atoms that share a pair of electrons |
| molecule | atoms held together by covalent bonds |
| hydrogen bond | bond between positive hydrogen atoms and negative atoms |
| cohesion | attraction between molecules in a substance |
| adhesion | attraction between molecules of different substances |
| solution | mixture of substances |
| solvent | substance that is greater and dissolves other substance in the solution |
| solute | substance that is dissolved in the solution |
| pH | solution's acidity |
| acid | compound that releases a proton in water |
| base | compound that removes a proton from water |
| monomer | smaller molecule in a polymer |
| polymer | molecule made of many linked monomers |
| carbohydrates | molecules made of carbon, hydrogen and oxygen |
| monosaccharides | simple carbohydrates |
| disaccharides | two bonded monosaccharides |
| polysaccharides | chain of monosaccharides |
| lipids | nonpolar chained molecules |
| fatty acids | chains of carbon and hydrogen making lipids |
| saturated fatty acid | lipid with maximum number of hydrogen atoms |
| unsaturated fatty acid | lipid with fewer hydrogen atoms |
| phospholipid | lipid with polar phosphate head and nonpolar tails |
| triglyceride | lipid with tails and no head |
| cholesterol | lipid in a ring structure |
| protein | polymer made of amino acids |
| amino acids | monomers made of CHON |
| peptide bonds | covalent bonds between amino acids |
| polypeptide | chain of amino acids and peptide bonds forming a protein |
| nucleic acids | polymers containing genetic information |
| nucleotide | monomer that makes nucleic acids |
| chemical reactions | process that changes substances by breaking and forming bonds |
| reactants | substances changed during chemical reactions |
| products | substances made during chemical reactions |
| bond energy | amount of energy needed to break bonds |
| equilibrium | when products and reactants are made at the same rate |
| activation energy | amount of energy needed to start a chemical reaction |
| exothermic | reaction releasing more energy than it absorbs |
| endothermic | reaction absorbing more energy than it releases |
| catalyst | substance that decreases the activation energy needed to start a chemical reaction |
| enzyme | catalysts for chemical reactions in living things |
| substrates | specific reactants enzymes act on |
| cell theory | cells make organisms, are produced by other cells, and is the most basic unit of life |
| cytoplasm | substance containing dissolved molecules in cells |
| organelles | specific structures that perform distinct processes in cells |
| prokaryotic cells | cell without a nucleus or organelles |
| eukaryotic cells | cells with a nucleus and organelles |
| cytoskeleton | proteins that change to meet the needs of the cell |
| nucleus | organelle that stores genetic information inclosed in the nuclear envelope |
| endoplasmic reticulum | organelle that helps make proteins and lipids |
| ribosomes | organelles that link amino acids to make proteins |
| golgi apparatus | organelle that modifies, packages, and transports proteins |
| vesicles | sacs that transport molecules |
| mitochondria | organelle that supplies energy for the cell |
| vacuole | storage organelle |
| lysosomes | organelles that contain enzymes to break down old organelles |
| centrioles | cylinders that divide DNA in cell division |
| cell wall | rigid outer layer for plant cells |
| chloroplasts | organelles that carry out photosynthesis |
| cell membrane | boundary between the cell and environment made up of phospholipids |
| fluid mosaic model | model showing the arrangement of molecules in the cell membrane |
| selective permeability | ability allowing specific materials to cross |
| receptor | protein that recieves a signal molecule and reacts |
| passive transport | movement of molecules across a cell membrane without energy |
| diffusion | movement of molecules from higher to lower concentration |
| concentration gradient | difference in the concentration of a substance in locations |
| osmosis | diffusion of water |
| isotonic | solution where substance concentration in and out of the cell is the same |
| hypertonic | solution where substance concentration is greater outside of cell, causing water to leave the cell and shrink |
| hypotonic | solution where substance concentration is greater in cell, causing water to enter the cell and expand |
| facilitated diffusion | molecules diffused in proteins across the cell membrane |
| active transport | movement of molecules across a membrane against the concentration gradient using ATP energy |
| endocytosis | process of engulfing molecules in the cell membrane to move them inside a cell |
| exocytosis | process of engulfing molecules in the cell membrane from a vesicle to move them outside a cell |
| ATP | molecule that transfers energy from from food breakdown to cell processes |
| ADP | lower energy molecule that can be converted into ATP |
| chemosynthesis | process by which organisms use chemical energy from ocean volcanoes |
| photosynthesis | process that captures light energy and converts it to sugar |
| chlorophyll | molecule in chloroplasts that absorbs light energy |
| thylakoids | coin shaped compartments that contain chlorophyll |
| light-dependant reactions | capture energy from sunlight and transfer it into ATP |
| light-independant reactions | use energy from ATP to make sugars |
| photosynthesis equation | 6CO2 and 6H2O and light - C6H12O6 and 6O2 |
| photosystems | series of light absorbing pigments and proteins that capture and transfer energy |
| electron transport chain | series of proteins in a membrane that transfer electrons to make ATP from ions and ADP |
| ATP synthase | complex enzyme which ions and ADP travel through to become ATP |
| Calvin cycle | chemical reaction chain using carbon dioxide, ATP and NADPH to make glucose |
| cellular respiration | process that releases chemical energy from sugars to make ATP |
| aerobic | with oxygen |
| anaerobic | without oxygen |
| glycolosis | glucose is split into two three-carbon molecules and ATP is made |
| Krebs cycle | process produces carbon dioxide and molecules to transport energy |
| fermentation | process that removes electrons from pyruvate in anaerobic respiration so that gylcolosis may continue |
| lactic acid | product of fermentation |
| alcoholic fermentation | yeast fermentation that produces alcohol |
| cell cycle | regular pattern of growth |
| mitosis | division of the cell nucleus and its contents |
| cytokinesis | divides cell cytoplasm |
| chromosome | continuous thread of DNA |
| histones | group of proteins that condense and wrap DNA |
| chromatin | loose combination of DNA and proteins |
| chromatid | one half of a duplicated chromosome |
| centromere | region of the condensed chromosome that holds together sister chromatids |
| telomeres | ends of chromatids that are made of nucleotides that do not form genes |
| prophase | DNA condenses into chromosomes while the cell prepares to divide |
| metaphase | spindle fibers align the chromosomes |
| anaphase | chromatids are separated |
| telophase | nuclear membranes reform and DNA uncoils |
| interphase | cell copies its DNA and grows in preparation for division |
| growth factor | proteins that stimulate cell division |
| apoptosis | programmed cell death |
| cancer | uncontrolled cell growth |
| tumor | disorganized clumps of cancer cells |
| benign | tumor where cancer cells are clustered together |
| malignant | tumor where cancer cells can break away |
| metastasize | cancer cells break away from tumors |
| carciniogens | substances known to produce or promote cancer development |
| asexual reproduction | creation of offspring from a single parent |
| binary fission | asexual reproduction of a single celled organism by division into two equal parts |
| budding | parent organism grows a small projection from itself creating a new organism |
| fragmentation | parent organism splits into pieces creating new organisms |
| tissues | groups of cells that work together to perform a similar function |
| organs | groups of tissues that work together to perform a specific function |
| organ systems | organs that carry out similar functions |
| cell differentiation | process in which unspecialized cells develop into their mature forms and functions |
| stem cells | unique type of body cells that can divide themselves and can both develop into specialized cells and remain undifferentiated |
| embryonic stem cells | stem cells taken from a embryo |
| totipotent | stem cells from a fertilized egg that can make all cells |
| pluripotent | stem cells from an embryo that can make almost all cells |
| multipotent | stem cells from adults that can become other closely related cells |
| somatic cells | cells that make up body tissue and organs |
| germ cells | cells in reproductive organs |
| gametes | sex cells developed from germ cells |
| homologous chromosomes | two inherited chromosomes from parents that have copies of the same genes |
| autosomes | chromosomes 1 to 22 that are not related to the sex of an organism |
| sex chromosomes | chromosomes that directly control the development of sexual characteristics |
| sexual reproduction | fusion of two gametes resulting in offspring |
| fertilization | fusion of an egg and sperm cell |
| diploid | cell that has two copies of each chromosome |
| haploid | gametes that have only one copy of each chromosome |
| meiosis | nuclear division of a diploid cell into four haploid cells |
| gametogenesis | production of gametes |
| spermogenesis | production of sperm cells |
| oogenesis | production of an egg cell and three polar bodies |
| sperm | male gamete |
| egg | female gamete |
| polar bodies | other cells produced by meiosis that are broken down |
| trait | distinguishing characteristics that are inherited |
| genetics | study of biological inheritance patterns |
| purebred | genetically uniform line of species |
| cross | mating of two organisms |
| law of segregation | organisms inherit two copies of each gene and donate only one copy in their gamete |
| allele | alternative forms of genes |
| locus | specific location on homologous chromosomes where a gene is |
| homozygous | two of the same allele at the same locus |
| heterozygous | two different alleles at the same locus |
| genome | genetic material of an organism |
| genotype | genetic makeup of a specific set of genes |
| phenotype | physical characteristics of an organism |
| dominant | allele expressed when two different alleles are present in a genotype |
| recessive | allele not expressed unless two copies are present in a genotype |
| Punnett square | grid system for predicting all possible genotypes resulting from a cross |
| monohybrid cross | crosses of one specific trait |
| testcross | cross between recessive organism and unknown genotype organism |
| dihybrid cross | crosses of two different traits |
| law of independant assortment | allele pairs separate independantly of each other during meiosis |
| probability | likelihood that a particular event will happen |
| crossing over | exchange of chromosomes segments between homologous chromosomes |
| genetic linkage | genes located close together are inherited together |
| recombination | mixing of parental alleles |
| carrier | organism that is heterozygous for an allele that does not show symptoms and can pass on the disease |
| sex linked genes | genes located on the sex chromosome |
| X chromosome inactivation | one of the two X chromosomes in randomly turned off leaving a patchwork of cells |
| incomplete dominance | heterozygous phenotype is between the homozygous phenotypes |
| codominance | neither trait is dominant or recessive and are both fully expressed |
| polygenic traits | traits produced by two or more genes |
| linkage maps | maps of relative locations of genes on a chromosome |
| pedigree | chart of phenotypes and genotypes in a family that can determine carriers of recessive alleles |
| karyotype | picture of all chromosomes in a cell |
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