Terminology Flashcards
Cell wall
The external, non living, rigid structure enclosing the cell membrane of algal, plant, fungi and most prokaryotic cells. The primary constituent is cellulose (algae, plants and some fungi) chitin (some fungi) or polysaccharide (prokaryotes)
Nucleus
An organelle enclosed within its own double membrane and containing the chromosomes.
Chromosomes
The strand of DNA and protein that carries the genetic information of a cell.
Endoplasmic reticulum:
Network of flattened tubes providing a large surface area of membrane within the cell. It may be smooth or rough.
Ribosomes:
The cell organelle that translates the DNA code into a linear sequence of amino acids which collectively form proteins. Free ribosomes occur in the cytoplasm of prokaryotic or eukaryotic cells. Bound ribosomes are on the (rough) endoplasmic reticulum in eukaryotic cells.
Golgi apparatus:
The layer of flattened sacs receiving substances synthesised in the rough and smooth endoplasmic reticulum that are then modified and transported to various destinations.
Lysosomes:
Organelles arising from the rough endoplasmic reticulum and the Golgi apparatus containing enzymes that break down food particles and recycle damages organelles. They also play a role in controlled cell death - apoptosis.
Mitochondria:
An organelle that concerts chemical energy of organic molecules such as sugars into the chemical ATP that powers work within the cell. This requires oxygen - aerobic respiration.
Vacuoles:
A membranous sac in cytoplasm with a variety of functions (stores waste and nutrients). Part of osmoregulation.
Centrioles:
Paired organelles occurring just outside the nuclear membrane of animal cells and make protists and in cells of land plants that firm motile sperm - their function is uncertain.
Cilia:
Hair like extensions from the surface of some eukaryotic cells. I’m single celled organisms beating cilia move the whole cell, in multi cellular organisms cilia keeps fluid in motion over the cell surface.
Haploid:
Having a SINGLE set of chromosomes.
Diploid:
Having 2 sets of chromosomes,one from the male and one from the female parent.
Flagellae:
Long, whip like structures used for movement in some eukaryotic and prokaryotic cells. Their internal structure is different in eukaryotes and prokaryotes.
Chloroplast:
A membrane bound organelle occurring in plant and algal cells, it contains the photosynthetic pigments in a small amount of DNA (cDNA). Converts solar energy into sugars for photosynthesis.
Mitosis:
Cell division in eukaryotic cells where one cell gives rise to 2 daughter cells, each with the same chromosome numbers as the parent.
Meiosis:
The sequence of two cell divisions by which a diploid cell gives rise to 4 haploid daughter cells.
Diffusion:
The passive movement of dissolved molecules or ions from a region of high concentration to a region of low concentration.
Osmosis:
Diffusion of water across a differentially permeable membrane; takes place from a region of greater water potential to one of lesser water potential.
Photosynthesis:
The process autotrophs (an organism with the capacity to make its own food) by which solar energy is trapped in the chloroplasts and converted to chemical energy in the form of the bonds in ATP molecules.
Respiration:
The metabolic process in organisms by which organic molecules are oxidised to release energy, typically with CO2 and water as by-products (cellular respiration).
Chlorophyll:
The main light capturing pigment in plants and algae.
Natural selection:
The differential reproductive success of different genotypes as a result of some organisms being better adapted to their environment than others.
Artificial selection:
The differential reproductive success of different genotypes produced by human decisions about which organisms are used for breeding.
Mutation:
Heritable change due to an alteration in the nucleotide sequence or arrangement of DNA in an organism.
Stabilising selection:
Selection that favours phenotypes near the mean of the normal character distribution, leading to a reduction in variance around intermediate character states.
Disruptive selection:
Selection that favours phenotypes towards the extremes of normal character distribution, leading to a bimodal distribution of character values in a population.
Directional selection:
Selection that favours phenotypes towards one extreme of the normal character distribution, leading to a consistent directional change in the man value of a character in population.
Allopatric speciation:
Formation of separate species through divergent evolution in populations that ARE geographically isolated (compare with sympatric speciation).
Sympatric speciation:
Formation of separate species through divergent evolution in populations that are NOT geographically isolated (compare with allopatric).
Phylogeny:
The evolutionary history of relationships of a group of organisms.
Cladistics:
Method of determining the phylogeny or evolutionary relationships among taxa based on the occurrence of shared, derived character states.
Systematics:
The field of biology that aims to infer the phylogeny of organisms, classify them into a hierarchical series of groups and name the groups so classified.
Prokaryote:
Unicellular or multi cellular organism in the domains of bacteria and archaea. Comprising small cells with the plasma membrane encased within a cell wall. The DNA exists as a coiled circular strand.
Heterotrophic:
An organism that obtains energy by ingesting autotrophs or other autotrophs and accessing the energy stored in the bond of their organic molecules.
Autotrophic:
An organism with the capacity to make its own food.
Virus:
An infectious particle of protein nucleic acid.
Eukaryote:
A cell containing discrete membrane- bound organelles and with a membrane bound nucleus in which DNA is organised into chromosomes.
Commensalism:
Interaction between 2 species where one species benefits and the other is unaffected.
Mutualism:
Interaction between species where both species benefit.
Sexual reproduction:
Reproduction involving the union of the 2 haploid gametes to form a new diploid individual.
Asexual reproduction:
Reproduction that does not involve the union of 2 gametes. It results in the clonal offspring that are genetically identical to the parent and each other.
Gametophyte:
The haploid stage of a protist or plant life cycle that produces the sexual gamete.
Gamete:
A sex cell (usually haploid) that unites with another to form a zygote. Isogametes are of the same size. When one gamete is larger that the other it is referred to as the female gamete or egg- when smaller the male gamete or sperm.
Parapatric speciation:
Gradual speciation whereby new species are created from populations that maintain overlapping geographic zones of genetic contact.
Zoogeographical regions:
Faunal region
Kingdom Monera:
Blue green algae, prokaryote, autotroph, single celled and colonial, marine, freshwater and terrestrial, other root system, no gametes produced, no gametophyte or sporophyte, no xylem or phloem, no leaves, no pollination, no seeds, no ovary, no double fertilisation, water required for male gamete n/a.
Bacteria:
Microscopic organisms, single celled, prokaryote that cannot multiply by itself- needs a host
Archaea:
Single celled organisms, microbes, similar to bacteria.
Kingdom Protista:
Red algae, brown algae, green algae, Eukaryote, autotroph, mostly multicellular, mostly marine, brown has holdfast, green are sometimes attached, red has various attachment , gametes are produced, often sporophyte, no xylem or phloem, no leaves, no pollination, no seeds, no ovary, no fertilisation but transfer of male gametes does require water.
Lichen:
Composite organisms consisting of a symbiotic relationship between a fungus and a photosynthetic partner.
Fungi:
Eukaryotic, includes mould and yeasts and mushrooms, separate from plants and animals and bacteria. Cell walls contain chitin. Perform vital roles in nutrient cycling.
Sporophyte:
Spore producing phase in life cycle of a plant that exhibits alternation of generation.
Spore:
A reproductive structure, some of which are adapted for dispersal and surviving long periods of time in unfavourable conditions.
Mycelium:
The vegetative part of a fungus, consisting of a mass of branching, thread like hyphae.
Mycorrhizae:
A symbiotic association between a fungus and the roots of a vascular plant. Important. Component of soil life.
Kingdom Plantae:
Contains liverworts, mosses, ferns, conifers and flowering plants. Eukaryotic, autotrophic, multicellular, terrestrial (flowering all 3 environments), roots and rhizoids (liverworts, mosses and ferns)’ gametes are produced, sporophyte (ferns, conifers and flowering) gametophyte (moss and liverworts), xylem and phloem in ferns, conifers and flowering, pollination in conifers and flowering plants, seeds in conifers and flowering plants, ovary present in flowering plants, double fertilisation in flowering plants, transfer of male gamete requires water in mosses, liverworts and ferns.
Alternation of generation;
Life cycles of Protists and plants with alternating gametophyte and sporophyte stages.
