Exam 1 Vocab Flashcards
(153 cards)
1
Q
Level of biological organization:
A
Atoms to molecules, cells, tissues, organs, organ systems, organisms, populations, communities, ecosystems, biomes, biosphere
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Theory:
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An explanation of an aspect of the natural world and universe that has been repeatedly tested with the scientific method
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Hypothesis:
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A proposed explanation based on limited evidence
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Null hypothesis:
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The hypothesis is not the explanation
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Independent variable
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Not affected by the experiment, value does not change
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Dependent variable
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Changes with the experiment/ what is being tested
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Control:
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Provides a baseline for the experiment
8
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Treatment groups
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The item or subject that is manipulated
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X- axis
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Independent variable
10
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Y-axis
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Dependent variable
11
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DNA
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Deoxyribonucleic acid, stores genetic information, sugar-phosphate base
12
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Watson & Crick
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Used X-ray crystallography to determine that DNA was a double helix with antiparallel strands. Used the chargaff rule to determine nucleotides, determined nucleotides are linked through hydrogen bonding
13
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Franklin & Wilkins
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Researchers who helped Watson & Crick
14
Q
RNA
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Ribonucleic acid: a messenger that carries genetic information from DNA to the proteins in a cell
15
Q
Hershey-Chase Experiment
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Used the presence of phosphorous in DNA and sulfur in proteins ti confirm that DNA is the genetic material, not protein
16
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Polymer
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Any large molecule composed of small repeating units (monomers) bonded together
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Nucleotides
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A molecule consisting of a five carbon sugar, one or more phosphate groups, and a nitrogenous based
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Nitrogenous base
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Nitrogen containing biological compounds that form nucleosides
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Purines
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A class of double ringed nitrogenous bases found in nucleotides (Adenine, guanine)
20
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Pyrimidine
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A class of single-ringed nitrogenous bases found in nucleotides (Cytosine, uracil, thymine)
21
Q
Sugar-phosphate backbone
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The portion of the DNA double helix that provides structure and support to the molecule
22
Q
Complementary base pairing
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The association between specific nitrogenous based of nucleic acids stabilized by hydrogen bonding
23
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Phospodiester linkage
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Chemical linkage between adjacent nucleotides in DNA and RNA. Forms when the phosphate group of one nucleotide condenses with the hydroxyl group on the sugar of another nucleotide
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Q
Anti-parallel double helix
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Describes the opposite orientation of nucleic acid strands that are hydrogen bonded to one another
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Histone proteins
A member of a class of positively charged (basic) proteins associated with DNA in the chromatin of eukaryotic cells
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Chromosome
Gene- carrying structure consisting of a single long molecule of double stranded DNA and associated proteins
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DNA replication
The process of producing two identical replicas of DNA from the original DNA molecule
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Semi-conservative
The way DNA replicates, with each strand of an existing DNA molecule serving as a template to create a new complementary DNA strand
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Replication bubble
An unwound and open region of DNA where DNA replication occurs
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Replication fork
The Y shaped site where a double-stranded molecule is DNA is separated into two single strands for replication and on which DNA synthesis occurs
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Origin of replication
A particular sequence in a genome at which replication is initiated
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Template strand
A strand of RNA or DNA used to make a new, complementary strand via complementary base pairing
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Non-template strand
The strand of DNA that is not transcribed during synthesis of RNA
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Leading strand
The new strand of DNA that is synthesized in one continuous piece in a direction that follows the replication fork
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Lagging strand
The new strand of DNA that is synthesized discontinuously (as a series of short pieces that are later joined) in a direction moving away from the replication fork
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DNA polymerase
An enzyme that catalyzes the synthesis of DNA
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Central dogma
The scheme for information flow in in the cell (DNA transcription RNA translation PROTEIN)
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Transcription
The process that uses a DNA template strand to produce complementary RNA
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Translation
The process by which a polypeptide is synthesized from information in codons of messenger RNA
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mRNA
Messenger RNA, carried information from DNA to proteins
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Ribosome
A large macro molecular machine that synthesized proteins by using the genetic information encoded in mRNA
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Triplet
A code in which a “word” of three letters encodes one piece of information
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Codon
A sequence of 3 nucleotides in DNA or RNA that codes for an amino acid or a stop signal for protein synthesis
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Amino acid
A small organic molecule with a central carbon atom bonded to an amino acid group, a carbonyl group, a hydrogen atom, and a side chain
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Protein
A macromolecule consisting of one or more polypeptide chains
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Polypeptide
A chain typically consisting of 50 or more amino acids linked together by peptide bonds
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Enzyme
A protein catalyst used by living organisms to increase the rate of biological reactions
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Start codon
The AUG triple in mRNA where protein synthesis begins; codes for the amino acid methionine
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Stop codon
Any of the three mRNA triplets (UAG, UGA, or UAA) that cause the termination of protein synthesis
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Base pair wobble
A pairing between two nucleotides in RNA molecules that does not follow Watson-Crick base pair rules
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Gene
A section of DNA that contains the regulatory sequences and coding information for the transcription of one or more related RNA molecules, some of which encode polypeptides
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Loci/locus
A gene’s physical location on a chromosome
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Chromatin
The complex of DNA and proteins, mainly histones, that compose eukaryotic chromosomes.
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Homologous chromosome
In diploid organisms, a member of a pair of chromosomes that are similar in size, shape, and gene content
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Sister chromatid
The paired, double stranded DNA copies of a recently replicated chromosome. Connected tightly at the centromere and eventually separate during anaphase of mitosis or meiosis II
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Centromere
The region of a replicated chromosome where the two sister chromatic a are joined most tightly. The kinetochore is formed during the M phase
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Karyotype
The distinctive appearance of all the metaphase or prometaphase chromosomes in an individual, including the number of chromosomes, their length, and their banding patterns
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Diploids
A cell or organism with two sets of chromosomes
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Haploid
A cell or organism with one set of chromosomes
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Gene expression
The entire set of processes, including transcription and translation, that convert the information in DNA into a product of a gene, most commonly a protein, that contributes to the phenotype of a cell organism
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Genotype
The alleles of a gene present in a given individual
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One gene, one enzyme hypothesis
The theory that each gene directly produces a single enzyme
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Phenotype
The detectable traits of an individual
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Alleles
A particular version of a gene
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Dominant allele
An allele whose phenotypic effect is observed when it is present in homozygous or heterozygous form
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Recessive allele
An allele whose phenotypic effect is observed only in homozygous individuals
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Homozygous
Having two identical alleles of a gene
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Heterozygous
Having two different alleles of a gene
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Mutation
Any permanent change in the hereditary material of an organism
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Point mutation
A mutation that results in a change in or an insertion or deletion of a single base pair in DNA
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Silent mutation
A mutation that changes the sequence of a codon without changing the amino acid that is specified
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Missense mutation
A point mutation that changes one amino acid for another within a protein
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Nonsense mutation
A point mutation that converts an amino-acid-specifying codon into a stop codon
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Frameshift mutation
The addition or deletion of one or a few base pairs in a coding sequence that shifts the reading frame of the mRNA
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Chromosome mutation
Any change in the chromosome number, or the change in the composition of individual chromosomes as a result of inversions, translocations, deletions, or duplications during cell division
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Chromosome deletion
The loss of part of a chromosome
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Chromosome duplication
A chromosome abnormality that occurs when there is an extra copy of genetic material on the short arm
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Chromosome inversion
A chromosome rearrangement in which a segment of a chromosome is reversed end to end
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Chromosome translocation
When a chromosome breaks and the fragmented pieces reattach to different chromosomes
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Gregor Mendel
The father of genetics
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Blending inheritance
The theory that offspring inherit a blend of the parents genes
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Model organism
An organism selected for scientific study based on its features that make it easy to work with
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Pure breeding/true breeding lines
A strain that produces offspring identical to the parents when mates within the strain
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Genetic cross
The purposeful mating of two individuals resulting in the combination of genetic material in offspring
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Hybrids
The offspring of parents from two different strains
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Parental generation
The adults used in the first experimental cross of a breeding experiment
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F1
The first set of offspring
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F2
The second set of offspring
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Monohybrid cross
The mating between two homozygous parents that differ in alleles of one gene
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Particulate inheritance
Discrete particles are passed from parents to offspring
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Principle of segregation
A hybrid between two parents different in a set of characters posses both parental factors which subsequently segregate
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Gamete
A haploid reproductive cell that ca fuse with another haploid reproductive cell of the opposite sec to for a diploid zygote
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Punnet square
A squared diagram used to predict the genotypes of a particular cross or breeding experiment
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Independent assortment
The concept that each pair of hereditary elements segregates independently of alleles of other genes during meiosis
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Dependent assortment
Null hypothesis to independent assortment
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Mendelian inheritance
Patterns of how traits are passed from parent to offspring that follow the law of segregation, the law of dominance, and the law of independent assortment
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Dihybrid cross
A mating between two homozygous parents that differ in alleles of two different genes
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Linked genes
A physical association between two genes because they are on the same chromosome
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Meiosis 1
The first cell diction of meiosis in which synapsis, crossing over, and independent assortment occur
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Meiosis 2
The second cell division of meiosis, in which sister chromatids are separated from each other
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Maternal chromosome
The chromosome coming from the mother
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Paternal chromosome
The chromosome coming from the father
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Daughter cell
The result of a single dividing parent cell
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Independent assortment of chromosome
Genes independently separate from one another when reproductive cells develop
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Crossing over
The swapping of genetic material
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Random fertilization
There is a random chance that each egg and sperm will join one another
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Genetic recombination
The exchange of genetic material between different organisms which leads to production of offspring
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Population
A distinct group of individuals
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Variation
Various differences between biological species and individuals
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Gene pool
The stock of different breeding genes in an interbreeding population
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Allele frequency
The frequency of an allele in a population
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Equilibrium
The condition of achieving balance
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Hardy-Weinberg equilibrium
A state of agreement between observed allele frequencies in a population and allele frequencies found by the hardy-Weinberg principle
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Modern synthesis of evolution
The unified theory of evolution based on Mendelian genetics and Darwinian evolution
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Evolution
Any change in the heritable characteristics of a population
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Migration/gene flow
The introduction of genetic material from one population to another through migration
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Genetic drift
Variation in allele and genotypic frequencies in a population
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Founders effect
The reduction in genetic variation
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Bottleneck effect
A sharp reduction of a population due to things like natural disasters
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Admixed population
When a populations members possess recent ancestry from two or more sources
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Non-random mating
Any mating in a population where crosses between the various types of individuals do not occur in the frequencies that are expected by chance
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Positive assortative mating
Organisms choose to mate with similar organisms
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Negative assortative mating
Organism choose to mate with organisms different from themselves
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Inbreeding
Breeding between related individuals
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Homozygosity
The possession of two identical alleles
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Heterozygosity
Having two different alleles of a gene
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Inbreeding depression
The decline in average fitness that takes place when homozygosity increases and heterozygosity decreased in a population due to inbreeding
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Genetic rescue
A mitigation strategy designed to restore genetic diversity and reduce extinction risks in small, isolated and frequently inbred populations
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Typological thinking
Classifies things only in terms of the types they belong and view variation as abnormal
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Plato and the “perfect essence”
Claimed every organism was an example of a perfect essence, or type, created by god, and these types were unchanging
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Aristotle and the “great chain of being”
Species were fixed types organized into a sequence based on increased size and complexity
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Jean-Baptiste Lamarck
Developed the law of use and disuse and the law of inheritance of squired characteristics
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Use and disuse hypothesis
More frequent use of organs strengthens, develops, and enlarges then
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Inheritance of acquired characteristics hypothesis
All the acquisitions or losses on individuals are preserved and carried onto offspring
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Charles Darwin
Described variation among individuals in a populations, across different populations of the same species, and across closely related species
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Artificial selection
The identification by humans of desirable traits in plants and animals, and the steps taken to enhance and perpetuate those traits in future generations
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Natural selection
A process through which individuals with certain characteristics survive and reproduce at a higher rate because of those characteristics
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Fitness
The ability of an organism to survive and reproduce compared to other individuals in the population
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Four requirements of evolution
Variation, inheritance, struggle for existence, differential survival and reproduction
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Mechanisms of evolution
Mutation, gene flow, genetic drift, and selection
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Directional selection
Individuals at one phenotypic extreme are favored
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Stabilizing selection
Individuals with an intermediate phenotype are favored
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Disruptive selection
Individuals at both phenotypic extremes are favored
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Heterozygous advantage
When the heterozygous phenotype has a higher fitness than either homozygous dominant or recessive genotypes
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Adaptation
A characteristic of an organism that improves its fitness
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“Just-so” stories
A story that purports to explain how evolution happens but is just a theoretical explanation lacking evidence
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Sexual selection
Selection because of preference by one sex for certain characteristics in individuals of another sex
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Mate choice
Intersexual selection
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Mate competition
Intrasexual selection
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Intrasexual selection
Individuals of the same sex compete with each other to obtain mates
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Intersexual selection
Selection of an individual if one sex for mating by an individual of another sex
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Sexual dimorphism
Where the sexes of the same species exhibit different characteristics
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Bateman-Trivers hypothesis
Variances in matings and reproductive success are greater among the sex with “cheaper” gametes and in greater abundance
