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70 terms

NCEA Level 3 Biology: Molecular Genetics

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Adenine
(biochemistry) purine base found in DNA and RNA
Amino Acid
organic compounds containing an amino group and a carboxylic acid group
Autosome
any chromosome that is not a sex chromosome
Centromere
a specialized condensed region of each chromosome that appears during mitosis where the chromatids are held together to form an X shape
Chromatid
one of two identical strands into which a chromosome splits during mitosis
Chromatin
the readily stainable substance of a cell nucleus consisting of DNA and RNA and various proteins
Chromosome
a threadlike body in the cell nucleus that carries the genes in a linear order
Cytosine
One of the four aromatic bases found in DNA and RNA. Cytosine is a pyrimidine; it pairs with guanine.
Deoxyribose Sugar
Pentose sugar in Nucleotide
DNA
deoxyribonucleic acid, the material that contains the information that determines inherited characteristics
Gamete
a mature sexual reproductive cell having a single set of unpaired chromosomes
Genetic Code
the ordering of nucleotides in DNA molecules that carries the genetic information in living cells
Genome
the complete genetic material contained in an individual
Guanine
One of the four aromatic bases found in DNA and RNA. Guanine is a purine; it pairs with cytosine.
Histone
protein molecule around which DNA is tightly coiled in chromatin
Homologous
term used to refer to chromosomes that each have a corresponding chromosome from the opposite-sex parent
Meiosis
cell division that produces reproductive cells in sexually reproducing organisms
Mitosis
cell division in which the nucleus divides into nuclei containing the same number of chromosomes
Nucleic Acid
an organic compound, either RNA or DNA, whose molecules are made up of one or two chains of nucleotides and carry genetic information
Polypeptide Chain
A chain of amino acids linked together by peptide bonds.
Ribose Sugar
sugar used in RNA to make up the "backbone"
RNA
ribonucleic acid, a natural polymer that is present in all living cells and that plays a role in protein synthesis
Sex Chromosome
one of two chromosomes of the 23rd pair of human chromosomes, which determine an individual's gender
Somatic
of the body
Thymine
nitrogen base found ONLY in DNA that pairs with adenine
Uracil
The RNA version of thymine. Like thymine, this base also pairs with adenine.
Zygote
fertilized egg
Anaphase
the stage of meiosis or mitosis when chromosomes move toward opposite ends of the nuclear spindle
Anti Codon
group of three bases on a tRNA molecule that are complementary to an mRNA codon
Coding Strand
RNA binds to this strand of DNA & copies it
Codon
three-nucleotide sequence on messenger RNA that codes for a single amino acid
Complimentary Base Pairs
the sequence of the strand on one strand determinesthe sequence of bases on the other strand
Cytokinesis
division of the cytoplasm during cell division
Degenerate Code
a genetic code in which some amino acids may be encoded by more than one codon each.
Disulphide Bridge
The S-S linkage, i.e. between two sulfur atoms, that forms during the cross-linking of amino acids during protein synthesis.
DNA Ligase
an enzyme that eventually joins the sugar-phosphate backbones of the Okazaki fragments
DNA Polymerase
enzyme involved in DNA replication that joins individual nucleotides to produce a DNA molecule
Eukaryotic
A cell characterized by the presence of a nucleus and other membrane-bound organelles. Eukaryotes can be unicellular (protists) or multicellular (fungi, plants and animals).
Exon
expressed sequence of DNA; codes for a protein
Helicase
an enzyme that untwists the double helix at the replication forks, separating the two parental strands and making them available as template strands
Inducer
an agent capable of activating specific genes
Interphase
a period between two mitotic or meiotic divisions during which the cell grows, copies its DNA, and synthesizes proteins
Intron
sequence of DNA that is not involved in coding for a protein
Karyotype
photograph of chromosomes grouped in order in pairs
Lagging Strand
The strand in replication that is copied 3' to 5' as Okazaki fragments and then joined up.
Leading Strand
the new continuous complementary DNA strand synthesized along the template strand in the mandatory 5' --> 3' direction
Metabolic Pathways
Series of progressive chemical reaction steps involving energy production or conversion.
Metaphase
The chromosomes move to the center of the cell.
mRNA
messenger RNA; type of RNA that carries instructions from DNA in the nucleus to the ribosome
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.
Operator Site
The site that a repressor protein can bind to to prevent transcription
Operon
a group of genes that operate together
Prokaryotic
having cells that lack membrane-bound nuclei
Promoter Site
part of DNA molecule that indicates where the sequence of base pairs that make up a gene begin
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
Protein Synthesis
the formation of proteins by using information contained in DNA and carried by mRNA
Purines
nitrogeneous bases that have a double ring of carbon and nitrogen atoms such as adenine and guanine
Pyrimidines
nitrogenous bases that have a single ring of carbon and nitrogen atoms, such as cytosine and thymine
Regulator Gene
a genetic unit that regulates or suppresses the activity of one or more structural genes
Replication Fork
a Y-shaped point that results when the two strands of a DNA double helix separate so that the DNA molecule can be replicated
RNA Polymerase
An enzyme that links together the growing chain of ribonucleotides during transcription.
Structural Gene
a gene that codes for a product, such as an enzyme, protein, or RNA, rather than serving as a regulator
Telophase
the final stage of meiosis when the chromosomes move toward opposite ends of the nuclear spindle
Template Strand
The DNA strand that provides the template for ordering the sequence of nucleotides in an RNA transcript.
Transcription
(genetics) the organic process whereby the DNA sequence in a gene is copied into mRNA
Transcription Factor
A regulatory protein that binds to DNA and stimulates transcription of specific genes.
Transcription Unit
unit, a region of a DNA molecule that is transcribed into an RNA molecule
Translation
(genetics) the process whereby genetic information coded in messenger RNA directs the formation of a specific protein at a ribosome in the cytoplasm
Triplet
The three nucleotides of DNA which code for one amino acid
tRNA
transfer RNA; type of RNA that carries amino acids to the ribosome