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Unit 4 - VCE Biology - Area of Study 1 - Heredity

A set of keywords for Unit 4 VCE Biology, Area of Stuidy 1 - Heredity
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5' methyl cap
Cap placed on the mRNA to help protect the mRNA's stability as part of post transcription processing.
5' to 3'
Direction in which DNA replication and transcription occurs
9:3:3:1
The phenotypic ratio resulting from a dihybrid cross where both parents are heterozygous for each trait
Addition
A type of point mutation where, a nucleotide that doesn't belong is added to the DNA code. This changes the amino acid sequence and protein sequence.
Adenine
Nitrogenous base found in DNA and RNA; pairs with thymine in DNA and with uracil in RNA
Allele
An alternate version of a gene. eg: a gene may carry the code for one trait , but there can be many versions of the gene (e.g: trait = eye colour, alleles could be blue, brown, green eyes)
Amino acid
Monomer of a protein. They are organic compounds containing an amino group and a carboxylic acid group, typically composed of Carbon, Hydrogen, Oxygen, Nitrogen (and sometimes Sulfur)
Aneuploidy
An abnormality involving a chromosome number that is not an exact multiple of the haploid number (one chromosome set is incomplete)
Anti-codon
Group of three bases on a tRNA molecule that are complementary to an mRNA codon
Apoptosis
Programmed cell death - the cell uses specialized cellular machinery to kill itself
Autosome
Any chromosome that is not a sex chromosome
Binary fission
A form of asexual reproduction in single-celled organisms by which one cell divides into two cells of the same size
Blunt ends
Restriction fragments with no overlapping ends resulting from cleavage by a restriction enzyme
Cell Cycle
The regular sequence of growth and division that cells undergo
Centromere
A specialized condensed region of each chromosome that appears during mitosis where the sister chromatids are held together to form an X shape
Chiasma
A point of overlap of paired chromatids at which fusion and exchange of genetic material occurs during crossing over
Chromatid
One of two identical "sister" parts of a duplicated chromosome
Chromosomal Abnormality
Any genetic defect that occurs when errors in meiosis produce sperm or egg cells with incorrect numbers of chromosomes or with damaged chromosomes. ex Downs Syndrome (trisomy 21)
Chromosome
Threadlike structure within the nucleus containing the genetic information that is passed from one generation of cells to the next
Chromosome mutation
Pieces of chromosomes splitting and moving to give duplication, deletion, inversion and translocation.
Cloning
Making a genetically identical copy of DNA or of an organism
Co-dominance
Situation in which both alleles of a gene contribute to the phenotype of the organism
Codon
A specific sequence of three adjacent bases on a strand of DNA or RNA that provides genetic code for a particular amino acid
Complete dominance
A relationship in which one allele is completely dominant over another
Complimentary base-pairing rules
The 'rule' which nitrogenous bases of nucleotides follow, in DNA - Adenine binds with Thymine, Cytosine with Guanine. In RNA, Thymine is replaced by Uracil
Continuous variation
Variation measured on a continuum rather than in discrete units or categories (eg height in human beings).
Covalent Bonds
A chemical bond that involves sharing a pair of electrons between atoms in a molecule
Crossing over
The interchange of sections between pairing homologous chromosomes during the prophase of meiosis
Cytosine
A nitrogenous base found in DNA and RNA; pairs with guanine
Daughter strand
The newly made strand of DNA after DNA replication has occured
Deletion
A type of Point mutation, where a nucleotide is deleted from the length of DNA. If one base is deleted, all the codons from that point to the end will undergo a "frame-shift". Most (or all) of the amino acids coded for will be different
Denaturation
A structural change in a protein that results in loss of normal shape and a loss of its biological properties, due to heat or other factors.
Dihybrid Cross
A cross (mating) between two individuals, concentrating on tracking and predicting two definable traits in the offspring.
Diploid
An organism or cell having two sets of chromosomes or twice the haploid number. All normal autosomes with a nucleus are diploid
Discontinuous varitation
A type of variation in which members of a population can be grouped into a few non-overlapping groups/classes with respect to a trait. E.g. flower colour within a species of plant
DNA
Deoxyribonucleic Acid, the material that contains the information that determines inherited characteristics. DNA is a polymer of nucleotides bonded together by phosphodiester bonds
DNA amplification
Creation of many copies of a segment of DNA by the polymerase chain reaction
DNA Polymerase
Enzyme involved in DNA replication that joins individual nucleotides and elongates a new DNA molecule.
DNA profiling
The analysis of DNA fragments to see who they come from; compares genetic markers from noncoding regions that show variation between individuals (involves amplication for analysis)
DNA recombination
DNA recombination refers to the process where a DNA segment moves from one DNA molecule to another DNA molecule. Can result from crossing over of non-sister chromatids during meiosis.
DNA Replication
Process of copying a DNA molecule
DNA sequencing
Determining the exact order of the base pairs in a segment of DNA
Dominant
A genetic trait is said to be dominant if it always appears in the phenotype despite the presence of other alleles in the genotype.
Duplication
Change to a chromosome in which part of the chromosome is repeated
Egg
Female gamete - reproductive cell
Epistasis
The suppression of a gene by the effect of an unrelated gene
Eukaryote
An organism whose cell(s) have a nucleus and membrane bound organelles; e.g: animals, plants, protists, fungi
Exons
A coding region of a eukaryotic gene. Exons, which are expressed, are separated from each other by introns.
F1 Generation
The first generation of offspring obtained from an experimental cross of two organisms
F2 Generation
The second generation of offspring, obtained from an experimental cross of two organisms; the offspring of the F1 generation
Frame shift
DNA mutation in which a nucleotide or nucleotides (other than three in number) are added to or taken from the DNA sequence so that subsequent codons are read incorrectly
Gamete
Sex cells - e.g: sperm in males, eggs in females
Gel Electrophoresis
The separation of nucleic acids or proteins, on the basis of their size and electrical charge, by measuring their rate of movement through an electrical field in a gel.
Gene
A segment of DNA on a chromosome that codes for a specific trait
Gene delivery system
Methods of transferring genes into host cells
Gene expression
Conversion of the information encoded in a gene first into messenger RNA (transcription) and then to a protein (translation)
Gene mutation
A change in the sequence of the bases in a gene, which changes the structure of the polypeptide that the gene codes for.
Gene Probe
A short piece of single stranded DNA which is radioactively labeled that will bind to a complimentary target DNA or RNA strand.
Gene regulation
Regulation of transcription; controlled by an operon which varies the accessibility of the RNA polymerase to genes being transcribed
Gene Transfer
Movement of genetic information between organisms
Gene Transformation
The introduction of foreign DNA into a cell resulting in permanent change
Genome
The complete genetic material contained in an individual
Genotype
The particular alleles at specified loci present in an organism. That is, the combination of alleles for one trait, typically descibed as a combination of upper and lower case letters, e.g: TT or Tt or tt
Genotype ratio
The ratio of the genotypes that appear in offspring. Used to predict the liklihood of offspring possessing specific traits.
Guanine
A nitrogenous base found in DNA and RNA; pairs with Cytosine.
Haploid
An organism or cell having only one complete set of chromosomes, Gametes are haploids
Helicase
An enzyme that untwists the double helix of DNA at the replication forks.
Heterozygous
An organisms genotype may be heterozygous if it has 2 different alleles for a given trait. Denoted as Tt
Histone Proteins
A simple protein bound to DNA, involved in the coiling of chromosomes
Homologous Pair
The two members of a specific chromosome pair found in diploid cells, one of which comes from the individual's mother and the other from its father.
Homozygous
When an organism has 2 identical genes for a given trait. Can be homozygous dominant - 2 dominant alleles, denoted as 2 upper case letters (TT) or homozygous recessive - 2 recessive alleles, denoted as 2 lower case letters (tt).
Hydrogen Bonds
Very weak bond created by the attraction of a slightly positive hydrogen atom to a slightly negative portion of another moleculeB
Incomplete dominance
Situation in which one allele is not completely dominant over another, creates a blended phenotype.
Inheritance
Traits acquired via biological heredity from the parents
Insertion
A mutation involving the addition of one or more nucleotide pairs to a gene.
Introns
Long sequences of non-coding DNA. Introns are removed during RNA processing
Inversion
A kind of mutation in which the order of the genes in a section of a chromosome is reversed
IPMAT and C
Acronym for order of cell cycle processes (Interphase) and Mitosis - Prophase >Metaphase > Anaphase> Telophase and Cytokinesis
Lagging strand
The strand in replication that is copied 3' to 5' as Okazaki fragments and then joined up.
Leading Strand
The complementary DNA strand that is synthesized continuously along the template strand in the 5' to 3' direction.
Lethal alleles
Mutated genes that are capable of causing death.
Ligase
An enzyme that connects two fragments of DNA to make a single fragment; also called DNA ligase. This enzyme is used during DNA replication and is also used in recombinant DNA research.
Linkage
Traits that tend to be inherited together as a consequence of an association between their genes
Loci
Point on the chromosome where the gene is found
Meiosis
Cell division that produces reproductive cells in sexually reproducing organisms. produces haploid cells for sexual reproduction
Mitosis
Cell division in which the nucleus divides into nuclei containing the same number of chromosomes. Essential for growth and repair of an organism
Monohybrid Cross
A cross (mating) between two individuals, concentrating on tracking and predicting one definable trait in the offspring.
mRNA
Messenger RNA; type of RNA (produced through transcription) that carries instructions from DNA in the nucleus to the ribosome for translation.
mRNA transcript
mRNA that has been modified for exit out of the nucleus and into the cytoplasm. Introns removed, Exons joined together
Multiple alleles
Three or more forms of a gene that code for a single trait
Mutagen
Any agent (physical or environmental) that can induce a genetic mutation or can increase the rate of mutation
Mutations
Random errors in gene replication that lead to a change in the sequence of nucleotides; the source of all genetic diversity
Non-Disjunction
Error in meiosis in which homologous chromosomes fail to separate, resulting in gametes with too many or too few chromosomes
Nucleotide
Monomer of nucleic acids made up of a 5-carbon sugar, a phosphate group, and a nitrogenous base
Offspring
Product of reproduction, a new organism produced by one or more parents
Okazaki fragments
Short fragments of DNA that are a result of the synthesis of the lagging strand during DNA replication.
Operon
A unit of gene regulation and transcription in bacterial DNA that consists of a promoter, an operator, and one or more structural genes
Parent strand
In DNA replication, the DNA strand that is used as a template
Polymerase Chain Reaction
A method of producing thousands of copies of DNA segment using the enzyme DNA polymerase
Pedigree
A diagram that shows the occurrence of a genetic trait in several generations of a family
Peptide bond
The covalent bond that forms between the carboxyl group of one amino acid and the amino group of another amino acid.
Phenotype
The traits that appear in an individual as a result of its genetic make up (genotype) and often effected by the environment.
Phenotype ratio
The ratio of the phenotypes that appear in offspring.
Plasmid
Circular DNA molecule found in bacteria
Pleiotropy
A single gene having multiple effects on an individuals phenotype.
Point Mutations
Gene mutations involving changes in one or a few nucleotides - Deletion, Addition and Substitution are examples.
Poly A tail
A sequence of 50 to 250 adenine nucleotides added onto the 3' end of a pre-mRNA molecule as part of post transcription mRNA processing.
Polygenes
When multiple independent pairs of genes have similar and additive effects on the same characteristic. e.g: inheritance of skin color in humans.
Polypeptide
A polymer (chain) consisiting of many amino acids linked together by peptide bonds.
Polyploidy
Condition in which an organism has extra sets of chromosomes
Primer
A short segment of nucleic acid that serves as the starting point for DNA synthesis
Prokaryote
A unicellular organism that lacks a nucleus and membrane bound organelles
Promoter sequence
Series of DNA nucleotides (15-300 base pairs long) that serves as the site where RNA polymerase binds for transcription
Punnet Square
A chart that shows all the possible combinations of alleles that can result from a genetic cross
Pure breeding
Individuals that are homozygous that will always produce the same offspring when crossed together
Recessive
An allele that is only expressed in the phenotpye if there is not a dominant allele in the genotype is said to be recessive.
Recombinant
Offspring possessing a single chromosome, DNA molecule or new combination of alleles not present in the parents, .
Recombinant Plasmid
Plasmid that has had a particular gene inserted into it using restriction enzymes
Recombination
A combining of genes or characters different from what they were in the parents
Regulator Genes
Genes that control the expression of other genes
Replication Fork
A Y-shaped region on a replicating DNA molecule where new strands are growing.
Restriction Enzyme
Any of the enzymes that cut nucleic acid at specific restriction sites and produce restriction fragments
Ribo Nucleic Acid (RNA)
Ribonucleic acid; a nucleic acid that plays an important role in the production of proteins. Is single stranded
Ribosome
Structures in the cell on which proteins are assembled; made of RNA and protein.
RNA polymerase
Transcription enzyme that links RNA nucleotides together forming a RNA polynucleotide.
RNA primase
An enzyme that creates an RNA primer for initiation of DNA replication.
RNA processing
Modification of RNA transcripts, including splicing out of introns, joining together of exons, and alteration of the 5' and 3' ends
rRNA
ribosomal RNA; type of RNA that makes up part of the ribosome
Segregation
The separation of paired alleles during meiosis so that members of each pair of alleles appear in different gametes
Semi-conservative replication
In each new DNA double helix, one strand is from the original molecule, and one strand is new synthesized.
Sex chromosome
A chromosome that determines the sex of an individual. Males have a genotype of Xy, while females have a genotype of XX.
Sex linked genes
A gene that is carried on the X or Y chromosome
Sex linked inheritance
Inheritance of a genetic trait located on the sex chromosomes
Silent mutation
A mutation that changes a single nucleotide, but does not change the amino acid created, due to redundany of the genetic code.
Spliceosome
A complex assembly of proteins invovled in mRNA splicing, removing the introns, and joining exons.
Splicing
Removing introns from mRNA transcipt to leave only exons.
Sticky ends
Overhanging complementary ends that result from a cut by a restriction enzyme
Structural Genes
A DNA sequence that codes for a specific product
Substitution
Amutation in which a nucleotide or a codon in DNA is replaced with a different nucleotide
Sugar-Phosphate backbone
The alternating chain of sugar and phosphate to which DNA and RNA nitrogenous bases are attached.
Taq Polymerase
An enzyme that replicates DNA and remains stable in hot conditions, used in PCR.
Terminator Sequence
Sequence of bases at the end of a gene that signals the RNA polymerase to stop transcribing
Test Cross
the crossing of an individual of unknown genotype with a homozygous recessive individual to determine the unknown genotype
Thymine
Nitrogenous base found ONLY in DNA. Complimentary pairs with Adenine. Replaced by Uracil in RNA.
Trait
Specific characteristic that varies from one individual to another
Transcription
The process whereby the DNA sequence in a gene is copied into mRNA
Translation
The process whereby genetic information coded in messenger RNA directs the formation of a specific protein at a ribosome in the cytoplasm
Translocation
Change to a chromosome in which a fragment of one chromosome attaches to a nonhomologous chromosome
Triplet codon
Sequence of 3 Nitrogenous bases on mRNA that specify a particular amino acid
tRNA
Transfer RNA; type of RNA that carries amino acids to the ribosome during translation.
Uracil
Nitrogenous base found only in RNA (not in DNA). Replaces Thymine in RNA. Complementary paired with Adenine
X-Linked
The pattern of inheritance that results from genes located on the X chromosome