Science Term 3: Biology

Mutagen

________: an agent that causes a change in the genetic material of an organism.

Cytosol

________: Aqueous component of the cell cytoplasm, in which various organelles and particles are suspended.

Aneuploidy

________: The condition of having an abnormal number of chromosomes in a haploid set.

Gene loci

________ can be identified according to chromosome number, arm, and banding region.

Oncogene

________: A gene that has the potential to cause cancer.

Peptide

________: Two amino acids linked in a chain.

Pure breeding

________: Where all individuals have the same genetic information through generations.

SIngle nucleotide polymorphism

________: Locations on chromosomes that differ by only one base from one human to another.

Somatic

________: occurs in body cells and can not be inherited.

Analogous

________: Structures that appear similar or have the same function but are unrelated.

Prophase

________: DNA supercoils and chromosomes condense, the nuclear membrane breaks down, and centromeres go to opposite sides.

Transition

________: substitution of one purine for another purine or one pyrimidine by another pyrimidine.

Helicase

________: Enzyme that separates the DNA strands by breaking the hydrogen bonds between complementary base pairs.

Metaphase

________: Mitotic spindle connects centromeres and centrosomes, aligning the chromosomes to the center.

Hominidae

________: The family to which humans belong.

Homo

________: The genus to which humans belong.

Translation

________: The mRNA transcripts code for the production of polypeptides in ribosomes.

Transversion

________: substitution of a purine by pyrimidine and vice versa.

Australopithecus

________: A genus in the family Hominidae that is probably ancestral to the genus Homo.

Mitosis

________: Nuclear division, whereby each pair of sister chromatids are separated into two identical daughter nuclei.

Homologous pairs

________ are arranged by length.

Plasmids

________: Autonomous genetic structure that can replicate independently of the chromosome, usually in prokaryotes.

Morphology

________: The physical form or structure of an organism.

Directional

________: One phenotypic extreme is selected at the expense of another.

Genetic drift

________: Change in gene pool composition due to chance events.

Chiasma

________: The contact point between the two chromatids of a chromosome during meiosis.

Dichotomous keys

________: A method of identification where a group of organisms is repeatedly divided into two categories until each organism has been identified.

Cytokinesis

________ (in plants): vesicles form at the center of the cell to form a cell wall.

Haploid

________: one copy of each chromosome (n)

Telophase

________: Chromosomes de- condense as the nucleus reforms.

Evolution

________: Cumulative change in the heritable characteristics of a population.

Diploid

________: two copies (complete set) of each chromosome (2n)

Artifical classification

________: Classifies species based on non- predictive features.

Adaptive radiation

________: A rapid increase in the number of species with a common ancestor when members occupy niches with different conditions.

Germline

________: occur in sex cells (gametes) and is inherited.

Chromatin

________: a mixture of DNA and proteins found in cells normally.

Metastasis

________: The spread of cancerous tissue.

Gametogenesis

________: the production and differentiation of gametes from haploid cells.

Universality

________: All organisms use the same genetic code (few viral exceptions)

Phosphodiester bond

Nucleotides are connected to form polynucleotides through the sugar-phosphate backbone thanks to this covalent bond

Purines

Double-ringed chemical compound found in nitrogenous bases

Complementary pairs

Nitrogenous bases connected via hydrogen bonds

Messenger RNA (mRNA)

transcript copy of a gene that reads the sequence in base triplets (codon) in the ribosome

Ribosomal RNA (rRNA)

responsible for the synthesis of protein in ribosomes

Transfer RNA (tRNA)

serves as the physical link between the mRNA and the amino acid sequence that will align opposite to a specific codon, transporting the latter to ribosomes

Gene

a specific sequence of DNA that encodes for a particular protein

Alleles

different possible variations of a gene

Gene mutation

change in the nucleotide sequence of a gene

Genome

The complete set of DNA in an organism

Human genome

46 chromosomes

Gene splicing

The process used to add a gene into or remove genes from DNA

Gene therapy

The process of replacing a defective gene with a normal gene

Pluripotent embryonic stem cells

Cells that are able to self-renew by dividing and developing into the three primary groups of cells that make up a human body

Chromosome

Single double-stranded DNA molecule

Cytosol

Aqueous component of the cell cytoplasm, in which various organelles and particles are suspended

Diploid

two copies (complete set) of each chromosome (2n)

Haploid

one copy of each chromosome (n)

Homologous chromosomes

Paired maternal and paternal chromosomes found in diploid organisms

Karyograms

Chromosome profile of an individual organism

Chorionic villi sampling

Cells are extracted from the placental tissue

Amniocentesis

Cells are extracted from the amniotic fluid

Autoradiography

A technique used to visualize uncondensed chromosomes by John Cairns

Aneuploidy

The condition of having an abnormal number of chromosomes in a haploid set

Polyploidy

The condition of having an abnormal number of chromosome sets due to malfunction of cytokinesis

DNA replication

Duplicate DNA to create identical sister chromatids prior to cell division

Transcription

Synthesise an RNA sequence from a DNA template

Translation

The mRNA transcripts code for the production of polypeptides in ribosomes

Semi-conservative

When new DNA molecules form they are composed of one strand from the original template and one newly synthesized

Helicase

Enzyme that separates the DNA strands by breaking the hydrogen bonds between complementary base pairs

Polymerase

Enzyme that covalently joins free nucleotides to their exposed complementary base pairs by using the energy from cleaving two of the phosphates

Polymerase chain reaction

An artificial method of replication used to rapidly amplify DNA sequences

RNA polymerase

Binds DNA and breaks the H-bonds and covalently joins RNA nucleotides

Antisense strand

RNA strand that is transcribed (the sequence is complementary to RNA script)

Peptide

Two amino acids linked in a chain

Degeneracy

More than one codon may code for the same amino acid, allowing silent mutations

Interphase

An active period in the cell cycle where many key metabolic processes occur

S phase

DNA replication

G2 phase

cell growth and proof-reading

Chromatin

a mixture of DNA and proteins found in cells normally

Chromosome

Chromatin strands that are condensed for mitosis

Chromatid

one of the two identical halves of a chromosome

Mitosis

Nuclear division, whereby each pair of sister chromatids are separated into two identical daughter nuclei

Cytokinesis (in animals)

Microtube filaments form a cleavage furrow that contracts

Cytokinesis (in plants)

vesicles form at the center of the cell to form a cell wall

Necrosis

Uncontrolled cell death

Apoptosis

Controlled cell death

Cancer

caused by uncontrolled cell division

Tumors

abnormal cellular growths formed as a result of cancer

Metastasis

The spread of cancerous tissue

Mutagen

an agent that causes a change in the genetic material of an organism

Carcinogens

Mutagens that cause cancer

Meiosis

Cell division for gametes

Gametes

Haploid sex cells produced by sexually reproducing organisms

Female

ovum

Male

sperm

Gametogenesis

the production and differentiation of gametes from haploid cells

Bivalents

Homologous chromosomes associated in pairs

Chiasmata

a point at which paired chromosomes remain in contact during the first metaphase of meiosis

Crossing over

Homologous chromosomes connect via chiasmata to form bivalents (tetrads) and exchange small portions of genetic information

Random assortment

Homologous chromosomes line up in random orientation during metaphase I, giving humans 2^23 gamete combinations