BIO1011 Lecture Review Flashcards

Comprehensive vocabulary flashcards covering the cell cycle, inheritance patterns, transcription, translation, mutations, and population genetics from BIO1011 notes.

Eukaryotic chromosome

A structure composed of a long, linear molecule of DNA tightly coiled and associated with proteins (histones).

DNA replication

The process of creating an identical copy of a DNA molecule.

Leading strand

The DNA strand synthesised continuously in the $5'$ to $3'$ direction during replication.

Lagging strand

The DNA strand synthesised discontinuously in short fragments in the $5'$ to $3'$ direction.

Mitosis

A process involving the separation of sister chromatids and cell division to ensure accurate DNA replication and segregation.

Meiosis

A process that results in the production of four haploid cells.

Interphase

A phase of the cell cycle where cell growth and DNA replication occur, but not part of mitosis.

Okazaki fragments

Short DNA fragments synthesised on the lagging strand during DNA replication.

Prophase

The phase of the cell cycle where chromosomes actively condense and become visible under a light microscope.

Mitotic spindle

The structure responsible for aligning chromosomes at the metaphase plate and separating sister chromatids to opposite poles.

Telomeres

Structures at the ends of chromosomes that prevent the degradation of DNA ends and maintain chromosome stability.

Telomerase

An enzyme that is more active in stem cells than somatic cells, responsible for maintaining telomere length.

Cytokinesis

The physical division of the cytoplasm resulting in two separate daughter cells.

Aneuploidy

A condition where daughter cells have an abnormal number of chromosomes, often caused by disruptions in mitotic spindle assembly.

Autosomal inheritance

The inheritance of genes located on autosomal (non-sex) chromosomes.

Sex-linked inheritance

The inheritance of genes located on sex chromosomes ($X$ and $Y$).

Monohybrid cross

A genetic cross between parents that differ in only one trait or gene.

Dihybrid cross

A genetic cross between parents that differ in two traits or genes.

Incomplete dominance

A form of intermediate inheritance where one allele is not completely expressed over its paired allele, resulting in a blending of traits.

Codominance

A relationship where both alleles contribute to the phenotype of the heterozygote, and both are completely expressed.

Epistasis

The interaction of genes at two or more loci, where one gene masks the expression of another gene.

Pedigree

A diagram showing the occurrence and appearance of phenotypes of a particular gene and its ancestors across generations.

Allelic heterogeneity

The phenomenon where different mutations within the same gene can cause the same disease. example: Cystic Fibrosis cause by the CFTR gene

Locus heterogeneity

The phenomenon where mutations in different genes can cause the same disease phenotype. Example: Albinism

Penetrance

The proportion of individuals with a given genotype who express the associated phenotype.

Expressivity

The degree to which a phenotype is expressed in an individual.

Operon

A unit of linked genes that are regulated and transcribed together, typically found in prokaryotes.

Introns

Non-coding regions within a pre-mRNA transcript that are removed during splicing.

Exons

Coding regions of a gene that are joined together to form a mature mRNA molecule.

Transcription

The process by which information in a DNA sequence is copied into a complementary RNA sequence.

mRNA splicing

The process of removing introns from the pre-mRNA transcript and joining the exons.

Transcription factors

Proteins that bind to specific DNA sequences to control the rate of transcription of genetic information from DNA to mRNA.

Differential gene expression

The process by which cells selectively activate or inactivate specific genes, leading to cell specialization.

Enhancer

A regulatory DNA sequence in eukaryotes that can be located far upstream or downstream from the gene it regulates.

Alternative splicing

The process of combining different exons to produce various mRNA transcripts, thereby increasing protein diversity.

Translation

The process by which the genetic information encoded in mRNA is used to synthesise a polypeptide chain of amino acids.

Ribosome

The organelle that serves as the site of translation, binding to mRNA and facilitating amino acid assembly.

tRNA

Molecules that transport amino acids to the ribosome and match them to corresponding codons on the mRNA template.

Point mutation

A mutation that changes a single nucleotide base in DNA.

Silent, missense and nonsense

Frameshift mutation

A mutation caused by the insertion or deletion of nucleotides, which shifts the reading frame of the DNA sequence.

Silent mutation

A point mutation that has no effect on the final protein product.

Missense mutation

A mutation that results in a codon coding for a different amino acid.

Nonsense mutation

A mutation that leads to a premature stop codon in mRNA.

Restriction enzymes

Enzymes used in biotechnology to cut DNA at specific sites.

PCR (Polymerase Chain Reaction)

A technique used to amplify specific DNA segments, creating many copies for analysis.

Ubiquitin

A protein that tags other proteins for degradation.

Cloning vector

A tool used in genetic engineering to carry foreign DNA into a host cell.

Transgenic organism

An organism that contains DNA from another species.

Sanger sequencing

A method using dideoxynucleotides ($ddNTPs$) that terminate DNA synthesis to determine the DNA sequence.

CRISPR-Cas9

A gene-editing technology using a guide RNA and the Cas9 protein to cut DNA at specific locations for disabling genes or fixing mutations.

Polymorphisms

Genomic variations between individuals within a population that contribute to variations in traits.

Speciation

The evolutionary process by which new biological species arise from populations becoming reproductively isolated.

Genetic drift

The random fluctuation of allele frequencies due to chance events, more pronounced in small populations.

Gene flow

The movement of genes between populations, which can increase genetic variation within a population.

Hardy-Weinberg equation

$p^2 + 2pq + q^2 = 1$, used to calculate allele and genotype frequencies in a population.

Single nucleotide polymorphism (SNP)

A variation in a single nucleotide base in DNA.

Phylogenetic tree

A diagram showing the evolutionary relationships among organisms inferred from shared derived characters.

Founder effect

The loss of genetic variation that occurs when a new population is established by a small number of individuals.

Heterozygote advantage

A situation where heterozygotes have higher fitness than either homozygote, such as sickle cell trait providing malaria resistance.