Unit 2 Biology Flashcards

Deoxyribonucleic acid (DNA)

A double-stranded nucleic acid chain made up of nucleotides. DNA carries the instructions for proteins which are required for cell and organism survival

Gene

A sequence of DNA that codes for a protein product.

Genome

The complete set of DNA contained within an organism's haploid (n) set of chromosomes.

Allele

A gene with an alternate sequence of nucleotides, representing a variation of that gene.

Chromosome

A structure made of proteins and nucleic acids that carries genetic information.

Homologous Chromosomes

A pair of chromosomes of similar size and length, gene position, and centromere location, one inherited from the mother and the other from the father.

Karyotype

An image of a set of chromosomes from a cell that has been sorted by size, length, centromere position, and gene position.

Autosomal Chromosome

Any chromosome (1–22) in humans that is not a sex chromosome.

Sex Chromosome

a chromosome responsible for determining the biological sex of an organism. In humans, sex chromosomes can be either an X or Y chromosome

Aneuploidy

A variation in the usual number of chromosomes in a genome due to the addition or loss of a chromosome.

Polyploidy

The presence of additional sets of chromosomes in an organism's genome.

Haploid (n)

A cell with a single set of chromosomes; in humans, the haploid number is 23.

Diploid (2n)

A cell with two sets of chromosomes; in humans, the diploid number is 46.

Meiosis

A specialized form of cell division used to produce gametes in sexually reproducing organisms.

Non Disjunction

The failure of homologous chromosomes or sister chromatids to separate properly during cell division, leading to an unequal distribution of chromosomes in daughter cells.

Germline Cell

Cells involved in the generation of gametes in eukaryotes.

Gonads

The organs that produce gametes from germline cells.

Gametes

Reproductive cells that arise from germline cells and contain half the genetic material (n) of a somatic cell.

Sperm

A haploid male gamete produced through spermatogenesis in the testes.

Egg Cell

A haploid female gamete produced through oogenesis in the ovaries

Zygote

The diploid cell formed by the combination of two haploid gamete cells.

Genotype

The genetic composition of an organism at a particular gene locus, represented using letter symbols.

Phenotype

The physical or biochemical characteristics of an organism resulting from gene expression and the environment.

Homozygous

Having identical alleles for the same gene on homologous chromosomes.

Heterozygous

Having different alleles for the same gene on homologous chromosomes.

Dominant

The variant of a gene that masks the effect of a recessive allele of the same gene on a homologous chromosome.

Recessive

The variant of a gene that is masked by a dominant allele of the same gene on a homologous chromosome.

Complete Dominance

A pattern of dominance where only the dominant allele from the genotype of a heterozygous individual is expressed in the phenotype.

Co-dominance

A pattern of dominance where both alleles from the genotype of a heterozygous individual are expressed in the phenotype.

Incomplete Dominance

A pattern of dominance where neither allele from the genotype of a heterozygous individual is dominant, resulting in an intermediate phenotype.

Epigenetics

Changes to an organism’s phenotype resulting from modifications to gene expression.

Methylation

The process by which methyl (CH3) groups are added to particular nucleotides in a DNA segment, modifying gene expression.

Histone Modification

An epigenetic process where chemical groups attach to histone proteins, altering how DNA wraps around the histones.

Gene Expression

The process of reading the information stored within a gene to create a functional product, typically a protein.

Monohybrid Cross

A cross showing the inheritance of one trait or characteristic.

Autosomal Monohybrid Inheritance

The inheritance of one trait controlled by a gene located on an autosome.

Genotypic Ratio

The ratio of different genotypes expected among offspring from a genetic cross.

Phenotypic Ratio

The ratio of different phenotypes expected among offspring from a genetic cross.

Sex-linked Inheritance

The inheritance of a trait controlled by a gene located on a sex chromosome.

Sex-linked Gene

A gene located on a sex chromosome.

Epigenome

the entire set of chemical modifications within a cell/organism

Genetic Diversity

Refers to the amount of genetic variation that exists between individuals

Population

a group of individuals of the same species living in the same location

Gene Pool

The total number of individual alleles within a particular population

Sexual Reproduction

A form of reproduction where the fusion of two distinct haploid gametes to produce a single diploid zygote which has of two sets of chromosomes

Fertilisation

The process by which two gametes (such as sperm and egg cells) fuse and form a zygote

Pollination

A form of sexual reproduction in plants that involves the fusion of pollen (male gamete) and ovule (female gamete) and leads to the production of seeds

Asexual reproduction

Is a type of reproduction that involves a single parent and does not involve the fusion of gametes (sex cells) or fertilization

Clone

A clone is an organism or cell that is genetically identical to another organism or cell

Binary Fission

A type of asexual reproduction where one organism divides into two identical organisms

Budding

A type of asexual reproduction where a group of cells bud and break away from the original organism to form a clone

Fragmentation

A type of asexual reproduction where a parent organism breaks into fragments each of which may develop into individual clones

Vegetative Propagation

A type of asexual reproduction where a plant is grown from fragments such as stem or root cutting of its parents.

Sporogenesis

A type of asexual reproduction where spores form on the surface of the organism and are dispersed into the surroundings where they may develop into identical clones of the parent

Parthenogenesis 

A type of asexual reproduction where an embryo can develop from a single unfertilised gamete

Community

A group of interacting populations of different species in the same geographical region

Ecosystem 

A group of multiple communities interacting with one another and their physical environment. Ecosystems are made up both biotic and abiotic factors.

Carrying capacity

The maximum population size that an environment can sustain indefinitely

Population distribution

The range of geographical areas that members of a population can be found in

Population density 

The number of individuals in a population per unit area

Density-independent factors

Environmental factors that affect population growth but are not affected by population density

Density-dependent factors 

Environmental factors that affect population growth and become stronger as population density increases

Symbiosis

An interaction between two organisms of different species living in close proximity to each other

Mutualism

Interactions between two organisms of different species where both parties experience some overall benefit

Commensalism

Interactions between two organisms of different species where one gains some benefit while the other experiences no significant benefit or harm

Predation

Interactions between different species where one organism hunts and kills another organism for food

Parasitism

Interactions between two organisms of different species where one organism obtains nutrients at the expense of a host organism

Amensalism

Interactions between two organisms of different species where one organism experiences some negative effect while the other experiences neither a beneficial nor negative effect

interspecific competition

The competition for resources between members of different species

Intraspecific competition 

The competition for resources between members of the same species

Keystone species 

A species that has a disproportionately large effect on its ecosystem relative to its abundance or biomass.

Apex predator 

A predator that has no natural predators and is at the top of its food chain

Ecosystem engineer 

An organism that creates, significantly alters, or maintains the structure of an environment

Competition

Interactions between two or more organisms competing for the same resources

Population size

The number of individuals in a population

Country

An area traditionally owned and cared for by an Aboriginal language group or community, with deep spiritual, cultural and emotional connections to the land.

Structural adaptation

Evolved modifications to an organism’s physical structure.

Behavioural adaptation

Evolved modifications to an organism’s actions

Physiological adaptations

Evolved modifications to an organism’s internal functioning or metabollic processes.

Somatic Cell Nuclear Transfer

The transference of a somatic cell nucleus into an enucleated egg cell.

Embryo Splitting

The division of an early embryo into several individual embryos

Plant Grafting

The attachment of a stem of one plant (scion) to the stem of another plant with already developed root system (rootstock).