Biology
Terms
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- Prometaphase
- the stage of mitosis or meiosis in which the nuclear membrane disintegrates, the centrioles reach the poles of the cell, and the chromosomes continue to contract
- Crossing Over
- the interchange of sections between pairing homologous chromosomes during the prophase of meiosis
- Independent Assortment
- the random distribution of the pairs of genes on different chromosomes to the gametes
- Nucleotide
- The building block of a nucleic acid, consisting of a five-carbon sugar covalently bonded to a nitrogenous bas and a phosphate group.
- Grana
- stacks of thylakoid discs
- Recessive
- The inherited characteristic often masked by the dominant characteristic and not seen in an organism.
- Redox Reaction
- A chemical reaction involving the transfer of one or more electrons from one reactant to another; also called oxidation-reduction reaction.
- Nucleolus
- A specialized structure in the nucleus formed from various chromosomes and active in the synthesis of ribosomes
- Primase
- an enzyme in the replication apparatus that is responsible for making RNA primer
- Prophase
- the first stage of mitosis or meiosis in eukaryotic cell division, during which the nuclear envelope breaks down and strands of chromatin form into chromosomes
- Synapsis
- the side by side pairing of homologous maternal and paternal chromosomes at the start of meiosis
- Rubisco
- Ribulose carboxylase, the enzyme that catalyzes the first step of the Calvin Cycle (the addition of CO2 to ribulose biphosphate, or RuBP).
- Mitosis
- the usual method of cell division, characterized typically by the resolving of the chromatin of the nucleus into a threadlike form, which condenses into chromosomes, each of which separates longitudinally into two parts, one part of each chromosome being retained in each of two new cells resulting from the original cell
- Telophase
- the final stage of meiosis or mitosis, in which the separated chromosomes reach the opposite poles of the dividing cell and the nuclei of the daughter cells form around the two sets of chromosomes
- Fertilization
- when a sperm and an egg unite, results in a new individual with a full set of 46 chromosomes
- Chloroplast
- An organelle found only in plants and photosynthetic protists that absorbs sunlight and uses it to drive the synthesis of organic compounds from carbon dioxide to water. It consists of an inner and outer membrane, a thylakoid and thylakoid membrane, and stroma.
- P Generation
- parental generation, the first two individuals that mate in a generic cross
- Double Helix
- a molecule of DNA is double stranded, with two polynucleotides wrapped around eachother
- Telomere
- The protective structure at each end of a eukaryotic chromosome. Specifically, the tandemly repetitive DNA at the end of the chromosome's DNA molecule. See also repetitive DNA.
- Light Reactions
- The steps in photosynthesis that occur on the thylakoid membranes of the chloroplast and that convert solar energy to the chemical energy of ATP and NADPH, evolving oxygen in the process.
- Homologous Chromosomes
- chromosomes that have the same sequence of genes, that have the same structured, and that pair during meisosis
- Growth Factor
- A protein that must be present in the extracellular environment (culture medium or animal body) for the growth and normal development of certain types of cells; a local regulator that acts on nearby cells to stimulate cell proliferation and differentiation.
- Substrate Level Phosphorylation
- ADP obtains a phosphate group attached to a metabolic intermediate by a high-energy bond. the high reactivity of the bond in the metabolic intermediate enables the phosphate group to be transferred to ADP. however, most phosphate-containing metabolic intermediates do not contain high-energy bonds
- Photophosphorylation
- The process of generating ATP from ADP and phosphate by means of a proton-motive force generated by the thylakoid membrane of the chloroplast during the light reactions of photosynthesis.
- DNA Ligase
- A linking enzyme essential for DNA replication; catalyzes the covalent bonding of the 3' end of a new DNA fragment to the 5' end of a growing chain.
- Topoisomerase
- a protein that junctions in DNA replication, helping to receive strain in the double helix ahead of the replication fork
- Nucleic Acid
- A polymer (polynucleotide) consisting of many nucleotide monomers; serves as a blueprint for proteins and, through the actions of proteins, for all cellular activities. The types are DNA and RNA.
- Cell Cycle
- the cycle of growth and asexual reproduction of a cell, consisting of interphase (g1, s, g2 cycles) and mytotic phase (mytosis[division of the cell in prophase, prometaphase, metaphase, anaphase, and telophase cycles] & cytokinesis[splitting of the cell])
- Acetyl-CoA
- the acetylated form of coenzyme A, formed as an intermediate in the oxidation of carbohydrates, fats, and protein in animal metabolism.
- Recombinant Gamete
- gamets that arent the same genotype as the parents.
- Kinetochore
- A specialized region on the centromere that links each sister chromatid to the mitotic spindle
- Signal Receptors
- on the surface of cells where the signal must attach
- Oxaloacetate
- a salt of oxyle acid
- Stroma
- The fluid of the chloroplast surrounding the thylakoid membrane; involved in the synthesis of organic molecules from carbon dioxide to water.
- Homozygous
- allele combination with both parts of genotype identical (example: TT or tt)
- Unlinked Genes
- genes that arent in the same chromosome
- g1-Phase
- a period in the cell cycle during interphase, after cytokinesis and before the S phase. For many cells, this phase is the major period of cell growth during its lifespan
- Chromatin
- the material that makes up both mitotic and interphase chromosomes; a complex of proteins and DNA strands that are loosely coiled such that translation and transcription can occur
- Histone
- A small protein with a high proportion of positively charged amino acids that binds to the negatively charged DNA and plays a key role in its chromatin structure
- Polysaccharide
- A polymer of up to over 1000 monosaccharides, formed by dehydration reactions.
- Semiconservative Replication
- DNA replication in which each of the parental strands is read to make a complementary daughter strand, ethus each new DNa molecule is composed of half the parental molecule paired with a newly synthesized strand.
- Electron Transport Chain
- A sequence of electron carrier molecules (membrane proteins) that shuttle electrons during the redox reactions that release energy used to make ATP.
- ATP
- Biochemistry. adenosine triphosphate: an ester of adenosine and triphosphoric acid, C10H12N5O4H4P3O9, formed esp. aerobically by the reaction of ADP and an orthophosphate during oxidation, or by the interaction of ADP and phosphocreatine or certain other substrates, and serving as a source of energy for physiological reactions, esp. muscle contraction.
- Diploid
- (genetics) an organism or cell having two sets of chromosomes or twice the haploid number
- Sucrose
- a complex carbohydrate found in many plants and used as a sweetening agent
- Signal Transduction Pathway
- A mechanism linking a mechanical or chemical stimulus to a specific cellular response.
- Cell Cycle Check point
- places in the cell cycle that are sensitive to either internal cell conditions or external chemical signals which must be "correct" for the cell to progress past them
- Lagging Strand
- the discontinuously synthesized DNA strand that elongates in a direction away from the replication fork
- Calvin Cycle
- The second of two major stages in photosynthesis (following the light reactions), involving atmospheric CO2 fixation and reduction of the fixed carbon into carbohydrate.
- NADP
- Nicotinamide adenine dinucleotide phosphate, an acceptor that temporarily stores energized electrons produced during the light reactions.
- Bacteriophage
- A virus that infects bacteria; also called a phage.
- Dominant
- the form of a trait that appears to dominate or mask another form of the same trait.
- Cristae
- Infoldings of the inner membrane of a mitochondrion that houses the electon transport chain and the enzyme catalyzing the synthesis of ATP.
- F1 Generation
- the first generation of offspring from a experimental cross of two organisms
- Secondary Spermatocyte
- the result of meiosis I of the primary spermatocyte is this haploid which is smaller in size. two are made out of one primary spermatocyte, they are destined to undergo meiosis II (DNA is not replicated before division)
- Locus
- a gene's specific location along the length of a chromosome is called the gene's _____
- Monohybrid Cross
- An organism that is heterozygous with respect to a single gene of interest. all the offspring from a cross between parents homozgous for different alleles are monohybrids. For example, parents of genotypes AA and aa produce a genotype of Aa.
- Asexual Reproduction
- reproduction that does not involve the union of gametes and in which a single parent produces offspring that are genetically identical to the parent
- NAD
- Nicotinamide adenine dinucleotide, a coenzyme present in all cells that helps enzymes transfer electrons during the redox reactions of metabolism.
- Bacterial Transformation
- is the process by which bacterial cells take up naked
- Antiparallel
- Parallel, but running in opposite directions. The 5' end of one strand of DNA aligns with the 3' end of the other strand in a double-helix.
- Primary Spermatocyte
- the product of a mitotic division of a spermatogonium under the influence of FSH (follicle-stimulating hormone) after puberty. this cell is destined to undergo meisosis. it under goes a growth phase and then meiosis I takes place (DNA replicates before the division)
- Heterozygous
- allele combination with two different parts of genotype (example: Tt)
- Chlorophyll
- green pigment in plants that absorbs light energy used to carry out photosynthesis
- Single Strand Binding Protein
- binds to single-stranded DNA
- Parental Gamete
- the sperm of egg
- Genotype
- genetic makeup of an organism
- Chromosome
- A threadlike linear strand of DNA and associated proteins in the nucleus of eukaryotic cells that carries the genes and functions in the transmission of hereditary information
- Reduction
- The addition of electrons to a substance involved in a redox reaction.
- Allele
- one of the alternative forms of a gene that governs a characteristic, such as hair color
- Primer
- A polynucleotide with a free 3' end, bound by complimentary base pairing to the template strand, that is elongated during DNA replication.
- Heterotroph
- An organism that obtains organic food molecules by eating other organisms or their by-products.
- Chromatid
- one of two identical strands into which a chromosome splits during mitosis
- Endocrine Signals
- hormonal, long distance. signal released travels through blood vessels to target cell, affects only target cell with correct receptor
- Sex Linked Gene
- xy or xx from mom or dad
- Cellulose
- A structural polysaccharide of cell walls consisting of glucose monomers joined by glycosidic linkages
- Secondary Oocyte
- a haploid cell resulting from meiosis 1 in oogenesis which will become an ovum after meiosis 2
- Nitrogenous Base
- an organic base that contains nitrogen, such as a purine or pyrimidine; a subunit of a nucleotide in DNA and RNA
- Spindle
- fanlike microtubule structure that helps seperate the chromosomes during mitosis
- Monosaccharide
- The simplest carbohydrate, active alone or serving as a monomer for disaccharides and polysaccharides. Also known as simple sugars, the molecular formulas of monosaccharides are generally some multiple of CH20.
- Neurotransmittors
- a chemical messenger released from teh synaptic terminal of a neuron at a chemical synapse that diffuses across the synaptic cleft and binds to and stimulates the postsynaptic cell
- Sexual Reproduction
- reproduction involving the union or fusion of a male and a female gamete
- Cytokinesis
- organic process consisting of the division of the cytoplasm of a cell following karyokinesis bringing about the separation into two daughter cells
- F2 Generation
- the second generation of offspring, obtained from an experimental cross of two organisms; the offspring of the F1 generation
- Mitochondrial Matrix
- The fluid that fills the interior space of the mitchondrion.
- Photosystem
- Light-capturing unit located in the thylakoid membrane of the chloroplast, consisting of a reaction center surrounded by numerous light-harvesting complexes. There are two types of photosystems, I and II; they absorb light best at different wavelengths.
- g2-Phase
- the third, final, and usually the shortest subphase during interphase within the cell cycle in which the cell undergoes a period of rapid growth to prepare for mitosis. It follows successful completion of DNA synthesis and chromosomal replication during the S phase, and occurs during a period of often four to five hours
- Intermembrane Space
- the region between the inner membrane and the outer membrane of a mitochondrion or a chloroplast. The main function of the intermembrane space is nucleotide phosphorylation.
- Chemiosmosis
- An energy-coupling mechanism that uses energy stored in the form of a hydrogen ion gradient across a membrane to drive cellular work, such as the synthesis of ATP. Most ATP synthesis in cells occurs by this
- Linked Genes
- genes on the same chromosome, with likelyness to be inherited together
- Sex Chromosome
- (genetics) a chromosome that determines the sex of an individual
- Pyrimidine
- a nitrogenous base that has a single-ring structure; one of the two general categories of nitrogenous bases found in DNA and RNA; thymine, cytosine, or uracil
- Chiasma
- a point of overlap of paired chromatids at which fusion and exchange of genetic material occurs during prophase I of meiosis
- Citric Acid Cycle
- in all plants and animals: a series of enzymatic reactions in mitochondria involving oxidative metabolism of acetyl compounds to produce high-energy phosphate compounds that are the source of cellular energy
- Paracrine Signals
- target cells nearby the signal releasing cell
- Carbon Fixation
- The incorporation of carbon from carbon dioxide into an organic compound by an autotrophic organism.
- Autosome
- any chromosome that is not a sex chromosome
- ATP Synthase
- A cluster of several membrane proteins found in the mitochondrial crista (and bacterial membrane) because that function in chemiosmosis with adjacent electron transport chains, using the energy of a hydrogen ion concentration gradient to make ATP. This provides a port through which hydrogen ions diffuse into the matrix of a mitochondrian.
- Okazaki Fragment
- A short segment of DNA synthesized on a template strand during DNA replication. Many Okazaki fragments make up the lagging strand of newly synthesized DNA.
- Metaphase
- the stage in mitosis or meiosis in which the duplicated chromosomes line up along the equatorial plate of the spindle
- DNA Polymerase
- An enzyme that catalyzes the elongation of new DNA at a replication fork by the addition of nucleotides to the existing chain.
- Centromere
- a specialized condensed region of each chromosome that appears during mitosis where the chromatids are held together to form an X shape
- Zygote
- the cell resulting from the union of an ovum and a spermatozoon (including the organism that develops from that cell)
- Polar Bond
- a covalent bond in which electrons are shared unequally
- Pentose
- any monosaccharide sugar containing five atoms of carbon per molecule
- Interphase
- the period of the cell cycle during which the nucleus is not undergoing division, typically occurring between mitotic or meiotic divisions
- Respiration
- This process uses oxygen to break down food molecules to release energy. The function of the system is the exchange of gasses between the blood of the circulatory system and the environment. The system takes in oxygen for cell respiration and transfers it to the blood and removes carbon dioxide, a waste of cell respiration, from the bloodstream and releases it from the body. Chemical energy stored in nutrients is released for use in cells.
- Clone
- a group of genetically identical cells or organisms derived from a single cell or individual by some kind of asexual reproduction
- Glucose
- the form of sugar that circulates in the blood and provides the major source of energy for body tissues. When its level is low, we feel hunger.
- Nucleosome
- A structure composed of two coils of DNA wrapped around an octet of histone proteins. The nucleosome is the primary form of packagin of eukaryotic DNA.
- Protone-Motive Force
- The potential energy stored in the form of an electrochemical gradient generated by the pumping of hydrogen ions across biological membranes during chemiosmosis.
- Oxidation
- The loss of electrons from a substance involved in a redox reaction.
- Testcross
- a cross between an organism whose genotype for a certain trait is unknown and an organism that is homozygous recessive for that trait so the unknown genotype can be determined from that of the offspring
- Dihybrid Cross
- a cross between individuals that have different alleles for the same gene
- Cleavage Furrow
- A shallow groove in the cell surgace near the old metaphase plate
- Dehydrogenase
- an enzyme that oxidizes a substrate by transferring one or more protons and a pair of electrons to an acceptor, usually NAD/NADP or a flavin coenzyme such as FAD or FMN.
- Haploid
- (genetics) an organism or cell having only one complete set of chromosomes
- Cyclin
- A regulatory protein whose concentration fluctuates cyclically.
- Autotroph
- An organism that obtains organic food molecules without eating other organisms or substanes derived from other organisms. These use energy from the sun or from the oxidation of inorganic substances to make organic molecules from inorganic ones.
- Purine
- a nitrogenous base that has a double-ring structure; one of the two general categories of nitrogenous bases found in DNA and RNA; either adenine or guanine
- Carbohydrate
- A sugar (monosaccharide) or one of its dimers (disaccharides) or polymers (polysaccharides)
- Contractile Ring
- a ring of actin around an animal cell
- Pyruvate
- Organic compound with a backbone of three carbon atoms. Two molecules form as end products of glycolysis
- Citrate
- a salt or ester of citric acid
- Cytochrome
- An iron containing protein a component of electron transport chains in mitochondria and chloroplasts
- Helicase
- an enzyme that untwists the double helix at the replication forks, separating the two parental strands and making them available as template strands
- Phenotype
- The physical traits that appear in an individual as a result of its gentic make up.
- Deoxyribose
- a sugar that is a constituent of nucleic acids
- Anaphase
- the stage in mitosis or meiosis following metaphase in which the daughter chromosomes move away from each other to opposite ends of the cell
- Leading Strand
- the new continuous complementary DNA strand synthesized along the template strand in the mandatory 5' --> 3' direction
- Starch
- A storage polysaccharide in plants consisting entirely of glucose
- Virus
- A bacteriophage that infects a host cell, causing the host cell to create more of it to infect other cells.
- Metaphase Plate
- An imaginary plane during metaphase in which the centromeres of all the duplicated chromosomes are located midway between the two poles
- Replication
- (genetics) the process whereby DNA makes a copy of itself before cell division
- Chromatin
- the material that makes up both mitotic and interphase chromosomes; a complex of proteins and DNA strands that are loosely coiled such that translation and transcription can occur
- Fat
- lipid; made up of fatty acids and glycerol; protects body organs, insulates body, and stores energy in the body
- Disaccharide
- A double sugar consisting of two monosaccharides joined by dehyration synthesis
- Primary Oocyte
- diploid cell in prophase 1 of meiosis that can be hormonally triggered to develop into an ovum
- Nuclear Envelope
- A double membrane that surrounds the nucleus. Made of two lipid bilayers that seperate the nucleus from the cytoplasm
- Gamete
- a mature sexual reproductive cell having a single set of unpaired chromosomes
- Mitochondria
- the cells powerhouse, turning food into energy, it's where cellular respiration takes place. (Harvesting chemical energy).
- Phosphodiester Bond
- A phosphodiester bond is a group of strong covalent bonds between the phosphorus atom in a phosphate group and two other molecules over two ester bonds. Phosphodiester bonds are central to all life on Earth, as they make up the backbone of the strands of DNA.
- Meiosis
- a two stage type of cell division in sezually reproducing organisms that results in cells with half the chromosome number of the original cell
- Cell Plate
- A double membrane across the midline of a dividing plant cell between which the new cell wall forms during cytokenisis
- Photosynthesis
- the process by which plants and some other organisms use light energy to power chemical reactions that convert water and carbon dioxide into oxygen and high energy carbohydrates such as sugars and starches
- Tetrad
- the four chromatids in a pair of homologous chromosomes that come together as a result of synapsis during meiosis
- Glycolysis
- a metabolic process that breaks down carbohydrates and sugars through a series of reactions to either pyruvic acid or lactic acid and release energy for the body in the form of ATP
- Origin Of Replication
- The specific location on a DNa strand where replication begins.. Prokaryotes typically have a single origin of replication, while eukaryotes have several per chromosome.
- Thylakoids
- disk-shape sac in the stroma of a chloroplast; site of the light reaction in photosynthesis
- Replicaiton Fork
- A Y shaped region on a replicating DNA molecule where new strands are growing
- Karyotype
- a micrograph of the array of chromosomes visible in a cell during metaphase; a graphical display that shows and individual's chromosomes arranged in homologous pairs and in order of diminishing size
- Oxidative Phosphorylation
- the production of ATP using energy derived form the redox reactions of an electron transport chain
- Telomerase
- An enzyme that catalyzes the lengthening of telomeres. The enzyme includes a molecule of RNA that serves as a template for new telomere segments.
- s-Phase
- The S phase, short for synthesis phase, is a period in the cell cycle during interphase, between G1 phase and the G2 phase. Following G1, the cell enters the S stage, when DNA synthesis or replication occurs. At the beginning of the S stage, each chromosome is composed of one coiled DNA double helix molecule, which is called a chromatid. At the end of this stage, each chromosome has two identical DNA double helix molecules, and therefore is composed of two sister chromatids