Prepare for your AP Biology first semester final with this review and practice questions. This covers cell biology, genetics, evolution, and biochemistry fundamentals.
Q: chloroplast
Answer: organelle found in cells of plants and some other organisms that captures the energy from sunlight and converts it into chemical energy
Q: thylakoids
Answer: disk-shaped structures within a chloroplast that serve as the site for light harvesting in photosynthesis
Q: grana
Answer: a stack of thylakoids within a chloroplast
Q: stroma
Answer: region outside the thylakoid membranes in chloroplasts
Q: mitochondria
Answer: Powerhouse of the cell, organelle that is the site of ATP (energy) production
Q: mitochondrial matrix
Answer: The compartment of the mitochondrion enclosed by the inner membrane and containing enzymes and substrates for the Krebs cycle.
Q: cristae
Answer: Infoldings of the inner membrane of a mitochondrion that houses the electon transport chain and the enzyme catalyzing the synthesis of ATP.
Q: inner mitochondrial membrane
Answer: The membrane of the mitochondria that is the site of electron transport and chemiosmosis.
Q: outer mitochondrial membrane
Answer: the smooth membrane covering the outside of a mitochondrion
Q: Golgi apparatus
Answer: An organelle in eukaryotic cells consisting of stacks of flat membranous sacs that modify, store, and route products of the endoplasmic reticulum.
Q: cis end of Golgi apparatus
Answer: located near ER, acts as receiving department
Q: trans end of Golgi apparatus
Answer: gives rise to vesicles, acts as shipping department
Q: vesicles
Answer: small membrane sacs that specialize in moving products into, out of, and within a cell
Q: free ribosomes
Answer: scattered throughout the cytoplasm, the proteins they manufacture enter the cytosol
Q: bound ribosomes
Answer: attached to outside of ER or nuclear envelope- proteins that are destined for insertion into membranes or packaging certain organelles (ex: lysosome)
Q: lysosome
Answer: membrane-bound sac containing digestive enzymes that can break down proteins, nucleic acids, and polysaccharides
Q: endoplasmic reticulum
Answer: a cell structure that forms a maze of passageways in which proteins and other materials are carried from one part of the cell to another
Q: cell wall
Answer: a rigid layer of nonliving material that surrounds the cells of plants and some other organisms
Q: vacuole
Answer: a water-filled sac inside a cell that acts as a storage area
Q: peroxisome
Answer: organelle with various specialized metabolic functions; produces hydrogen peroxide
Q: microfilament
Answer: (actin filaments), two intertwined strands of actin, functions in mainenance of cell shape, changes in cell shape, muscle contraction, cell motility, cell division
Q: microtubules
Answer: (tubulin polymers), hollow tubes, function in maintenance of cell shape, cell motility, chromosome movements in cell division, organelle movements
Q: intermediate filaments
Answer: fibrous proteins supercoiled into thicker cables, (keratin), maintenance of cell shape, anchorage of organelles like nucleus, formation of nuclear lamina
Q: plasmodesmata
Answer: Open channels in the cell wall of a plant through which strands of cytosol connect from an adjacent cell.
Q: tight junctions
Answer: membranes of neighboring cells are actually fused forming continuous belts around cell to prevent leakage of extracellular fluid
Q: desmosomes
Answer: Points in which two cells are fastened together into strong sheets. Intermediate filaments anchor these. Also called anchoring junctions.
Q: gap junctions
Answer: provide cytoplasmic channels between adjacent animal cells
Q: cholesterol’s function in fluid mosaic model
Answer: wedged between phospholipid molecules in plasma membranes of animal cells, “temperature buffer”
Q: fibers of extracellular matrix function in fluid mosaic model
Answer: attach to peripheral proteins; help maintain cell shape & stabilizes location of membrane proteins
Q: glycolipid function in fluid mosaic model
Answer: covalently bonded to lipids, functions as marker that distinguishes one cell from another
Q: integral protein function in fluid mosaic model
Answer: penetrate hydrophobic core of lipid bilayer, function in transport, enzymatic activity, signal transduction, cell-cell recognition, and intercellular junction
Q: peripheral protein function in fluid mosaic model
Answer: not embedded in bilayer, attach to cytoskeleton and ECM
Q: glycoprotein function in fluid mosaic model
Answer: covalently bonded to proteins, functions as marker that distinguishes one cell from another
Q: phospholipid bilayer function
Answer: amphipathic molecule (hydrophobic region and hydrophilic region), fluidity, movement
Q: osmosis
Answer: diffusion of molecules through a semipermeable membrane from a place of higher concentration to a place of lower concentration until the concentration on both sides is equal
Q: diffusion
Answer: the process by which molecules move from an area of higher concentration to an area of lower concentration
Q: facilitated diffusion
Answer: the transport of substances through a cell membrane along a concentration gradient with the aid of carrier proteins
Q: active transport
Answer: energy-requiring process that moves material across a cell membrane against a concentration difference
Q: sodium potassium pump
Answer: a carrier protein that uses ATP to actively transport sodium ions out of a cell and potassium ions into the cell
Q: catabolic
Answer: A process in which large molecules are broken down
Q: anabolic
Answer: A process in which large molecules are built from small molecules
Q: cellular respiration
Answer: the process that releases energy by breaking down glucose and other food molecules in the presence of oxygen
Q: glycolysis
Answer: 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
Q: citric acid cycle
Answer: in cellular respiration, series of chemical reactions that break down glucose and produce ATP; energizes electron carriers that pass the energized electrons on to the electron transport chain
Q: electron transport chain
Answer: a series of molecules, found in the inner membranes of mitochondria and chloroplasts, through which electrons pass in a process that causes protons to build up on one side of the membrane
Q: chemiosmosis
Answer: 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
Q: ATP synthase
Answer: protein structure in cell mitochondria that uses energy from H+ ions to convert ADP to ATP
Q: alcoholic fermentation
Answer: anaerobic process in which cells convert pyruvic acid into carbon dioxide and ethyl alcohol; carried out by many bacteria and fungi such as yeasts
Q: lactic acid fermentation
Answer: series of anaerobic chemical reactions in which pyruvic acid uses NADH to form lactic acid and NAD+, which is then used in glycolysis; supplies energy when oxygen for aerobic respiration is scarce
Q: oxidation
Answer: The loss of electrons from a substance involved in a redox reaction.
Q: reduction
Answer: The addition of electrons to a substance involved in a redox reaction.
Q: NAD+
Answer: an organic molecule that serves as an electron carrier by being oxidized to NAD+ and reduced to NADH
Q: FAD
Answer: electron acceptor in the krebs cycle
Q: autotroph
Answer: organism that can capture energy from sunlight or chemicals and use it to produce its own food from inorganic compounds; also called a producer
Q: heterotroph
Answer: organism that obtains energy from the foods it consumes; also called a consumer
Q: light reactions
Answer: 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.
Q: Calvin cycle
Answer: reactions of photosynthesis in which energy from ATP and NADPH is used to build high-energy compounds such as sugars
Q: centromere
Answer: the region of the chromosome that holds the two sister chromatids together during mitosis
Q: mitosis
Answer: cell division in which the nucleus divides into nuclei containing the same number of chromosomes; produces same number of cells started with
Q: centrosome
Answer: Central microtubule organizing center of cells. In animal cells, it contains two centrioles.
Q: centriole
Answer: in animal cells, a cytoplasmic organelle that organizes the mitotic spindle fibers during cell reproductions
Q: aster
Answer: star-shaped structure formed in the cytoplasm of a cell having fibers like rays that surround the centrosome during mitosis
Q: sister chromatids
Answer: Replicated forms of a chromosome joined together by the centromere and eventually separated during mitosis or meiosis II.
Q: daughter chromosomes
Answer: Sister chromatids that are separated by mitosis
Q: interphase G1
Answer: part of cell cycle when cell grows to normal size and makes organelles
Q: interphase S
Answer: synthesis: DNA is replicated, cell now has 2 copies of DNA; each chromosome is copied, new copy is joined w/ old copy, identical copies – sister chromatids
Q: interphase G2
Answer: Period after DNA replication; cell prepares for division
Q: mitosis prophase
Answer: first and longest phase of mitosis, chromatin condenses into chromosomes and becomes visable, centrioles separate and move to opposite sides of the nucleus, spindle begins to form, nucluer envelope bracks down
Q: mitosis metaphase
Answer: second stage of mitosis where chromosomes line up across the center of the cell, mictotubles connect the centromere of each chromosome to the 2 poles of the spindle
Q: mitosis anaphase
Answer: third phase of mitosis where sister chromatids separate into individual chromosomes and are moved apart into two groups near the poles of the spindle, phase ends when chromosomes stop moving
Q: mitosis telophase
Answer: fourth and final stage of mitosis, distinct and condensed chromosomes begin to disperse into a tangle of dense material, nucleqar envelope re-forms around each cluster of chromosomes, spindle begins to break down, nucleolus becomes visable in each daughter nucleus- mitosis complete, but not cell division
Q: cytokinesis
Answer: division of the cytoplasm during cell division
Q: diploid cell
Answer: A cell containing two sets of chromosomes (2n), one set inherited from each parent.
Q: haploid cell
Answer: A cell containing only one set of chromosomes (n).
Q: meiosis
Answer: a process in cell division during which the number of chromosomes decreases to half the original number by two divisions of the nucleus, which results in the production of sex cells; produces4 haploid cells
Q: synapsis
Answer: the side by side pairing of homologous maternal and paternal chromosomes at the start of meiosis
Q: tetrad
Answer: the four chromatids in a pair of homologous chromosomes that come together as a result of synapsis during meiosis
Q: independent assortment
Answer: the random distribution of the pairs of genes on different chromosomes to the gametes
Q: meiosis interphase
Answer: chromosomes replicate. each produces 2 sister chromatids, which pair up. Synapsis, Stage that is no different than that of mitosis where the DNA duplicates and the chromosomes are not clearly discerned
Q: meiosis prophase I
Answer: 2nd stage of meiosis I; chromosomes condense and pair up to form tetrads and attach to spindles; Crossing over between the homologs(the exchange of genetic material b/w non-sister chromatids). The homologs pair up and exchange genes.
Q: meiosis prophase II
Answer: 1st stage of meiosis II, 6th stage of meiosis; new spindle forms and attaches to the centromeres
Q: meiosis metaphase I
Answer: 3rd stage of meiosis I; the tetrads line up in the middle of the cell
Q: meiosis metaphase II
Answer: 7th stage of meiosis, 2nd stage of meiosis II; chromosomes line up across center of cell, spindle fibers attach to each sister chromatid
Q: meiosis anaphase I
Answer: 4th stage of meiosis I; spindle fibers pull the homologs to opposite sides of the cell. Centromeres don’t divide- the chromatids remain connected
Q: meiosis anaphase II
Answer: 8th stage of meiosis, 3rd stage of meiosis II; centromeres divide, sister chromatids separate and move to opposite poles.
Q: meiosis telophase I
Answer: A nuclear envelopes form around the chromosomes. Chromosomes uncoil. Spindles disappear.
Q: meiosis telophase II
Answer: 9th and last stage of meiosis, 4th stage of meiosis II; nucleus reforms, cytokinesis occurs. Chromoatids are now chromosomes. Result is four haploid cells
Q: homozygous
Answer: term used to refer to an organism that has two identical alleles for a particular trait
Q: heterozygous
Answer: term used to refer to an organism that has two different alleles for the same trait
Q: multiple alleles
Answer: three or more forms of a gene that code for a single trait
Q: co-dominance
Answer: situation in which both alleles of a gene contribute to the phenotype of the organism
Q: incomplete dominance
Answer: creates a blended phenotype; one allele is not completely dominant over the other
Q: pleiotrophy
Answer: A single gene that affects more than one trait
Q: epistasis
Answer: a gene at one locus alters the phenotypic expression of a gene at a second locus
Q: x-linked
Answer: the pattern of inheritance that results from genes located on the X chromosome
Q: test cross
Answer: the crossing of an individual of unknown genotype with a homozygous recessive individual to determine the unknown genotype
Q: nondisjunction
Answer: error in meiosis in which homologous chromosomes don’t separate; gametes end up with wrong number of chromosomes
Q: translocation
Answer: change to a chromosome in which a fragment of one chromosome attaches to a nonhomologous chromosome
Q: deletion
Answer: occurs when a chromosomal fragment lacking a centromere is lost
Q: inversion
Answer: a chromosomal fragment may also reattach to the original chromosome but in the reverse orientation
Q: aneuploidy
Answer: A chromosomal aberration in which one or more chromosomes are present in extra copies or are deficient in number.
Q: DNA polymerase I
Answer: removes RNA nucleotides of primer from 5′ end and replaces them with DNA nucleotides
Q: helicase
Answer: an enzyme that untwists the double helix at the replication forks, separating the two parental strands and making them available as template strands
Q: DNA polymerase III
Answer: Adds new DNA nucleotides to a replicating DNA molecule, works in 5′-3′ direction
Q: nuclease
Answer: A team of enzymes that hydrolyze DNA and RNA into their component nucleotides
Q: DNA primer
Answer: A small piece of single-stranded DNA. It acts a signal, binding to and marking the piece of DNA which is to be copied in the polymerase chain reaction (PCR).
Q: primase
Answer: An enzyme that joins RNA nucleotides to make the primer using the parental DNA strand as a template.
Q: ligase
Answer: An enzyme that links the pieces of DNA together into a single DNA strand
Q: single strand binding proteins
Answer: Proteins that bind to and stabilize the signle strands of DNA exposed when helicase unwinds the double helix in preparation for replication.
Q: replication fork
Answer: a Y-shaped point that results when the two strands of a DNA double helix separate so that the DNA molecule can be replicated
Q: okazaki fragments
Answer: Small fragments of DNa produced on the lagging strand during DNa replication, joined later by DNA ligase to form a complete strand.
Q: leading strand
Answer: the new continuous complementary DNA strand synthesized along the template strand in the mandatory 5′ –> 3′ direction
Q: lagging strand
Answer: The strand in replication that is copied 3′ to 5′ as Okazaki fragments and then joined up.
Q: transcription
Answer: process in which part of the nucleotide sequence of DNA is copied into a complementary sequence in RNA
Q: codon
Answer: a specific sequence of three adjacent bases on a strand of DNA or RNA that provides genetic code information for a particular amino acid
Q: intron
Answer: sequence of a eukaryotic gene’s DNA that is not translated into a protein
Q: exon
Answer: expressed sequence of DNA; codes for a protein
Q: snRNPS
Answer: Located in nucleus, composed of RNA and protein, recognize splice sites on DNA sequences
Q: translation
Answer: (genetics) the process whereby genetic information coded in messenger RNA directs the formation of a specific protein at a ribosome in the cytoplasm
Q: anti-codon
Answer: group of three bases on a tRNA molecule that are complementary to an mRNA codon
Q: rRNA
Answer: The most abundant type of RNA, which together with proteins froms the structure of ribosomes. Ribosomes coordinate the sequential coupling of tRNA molecules to mRNA codons.
Q: tRNA
Answer: The type of RNA that binds to specific amino acids and transports them to the ribosome during protein synthesis
Q: aminoacyl tRNA synthetase
Answer: An enzyme that joins each amino acid to the correct tRNA.
Q: amino acids
Answer: small units that are linked together chemically to form large protein molecules