Biology Flashcards ( from higher SQA specifification)

Flashcards containing vocabulary terms and definitions related to DNA and the genome, metabolism and survival, and sustainability and interdependence.

Prokaryotes

A single circular chromosome and smaller circular plasmids.

Eukaryotes

Linear chromosomes, in the nucleus, which are tightly coiled and packaged with associated proteins. They also contain circular chromosomes in their mitochondria and chloroplasts. Yeast is a special example of a eukaryote as it also has plasmids.

DNA polymerase

Adds DNA nucleotides, using complementary base pairing, to the deoxyribose (3’) end of the new DNA strand which is forming.

Polymerase chain reaction (PCR)

Amplifies DNA using complementary primers for specific target sequences, using repeated cycles of heating and cooling to amplify the target region of DNA.

Messenger RNA (mRNA)

Carries a copy of the DNA code from the nucleus to the ribosome.

Transfer RNA (tRNA)

Folds due to complementary base pairing and carries its specific amino acid to the ribosome.

Ribosomal RNA (rRNA)

And proteins form the ribosome.

RNA splicing

The introns of the primary transcript are non-coding regions and are removed. The exons are coding regions and are joined together to form the mature transcript.

Cellular differentiation

The process by which a cell expresses certain genes to produce proteins characteristic for that type of cell, which allows a cell to carry out specialised functions.

Embryonic stem cells

Cells in the very early embryo can differentiate into all the cell types that make up the organism and so are pluripotent.

Tissue stem cells

Are involved in the growth, repair and renewal of the cells found in that tissue and are multipotent.

Genome

Is its entire hereditary information encoded in DNA and is made up of genes and other DNA sequences that do not code for proteins.

Mutations

Are changes in the DNA that can result in no protein or an altered protein being synthesised.

Single gene mutations

Involve the alteration of a DNA nucleotide sequence as a result of the substitution, insertion or deletion of nucleotides.

Evolution

The changes in organisms over generations as a result of genomic variations.

Natural selection

The non-random increase in frequency of DNA sequences that increase survival and the non-random reduction in the frequency of deleterious sequences.

Speciation

Is the generation of new biological species by evolution as a result of isolation, mutation and selection.

Genomic sequencing

The sequence of nucleotide bases can be determined for individual genes and entire genomes.

Metabolic pathways

Are integrated and controlled pathways of enzyme-catalysed reactions within a cell.

Anabolic reactions

Build up large molecules from small molecules and require energy.

Catabolic reactions

Break down large molecules into smaller molecules and release energy.

Glycolysis

Is the breakdown of glucose to pyruvate in the cytoplasm.

Fermentation

Takes place in the cytoplasm of cells in the absence of oxygen and results in much less ATP being produced than in aerobic respiration.

Conformers

Internal environment is dependent upon external environment, use behavioural responses to maintain optimum metabolic rate, have low metabolic costs and a narrow range of ecological niches.

Regulators

Maintain their internal environment regardless of external environment, use metabolism to control their internal environment, which increases the range of possible ecological niches, this regulation requires energy to achieve homeostasis, which increases their metabolic costs.

Dormancy

Is part of some organisms’ life cycle to allow survival during a period when the costs of continued normal metabolic activity would be too high.

Migration

Avoids metabolic adversity by expending energy to relocate to a more suitable environment.

Micro-organisms growth media

Require raw materials for biosynthesis as well as an energy source.

Recombinant DNA technology

Involves the use of recombinant plasmids and artificial chromosomes as vectors.

Food security and sustainable food production

Increase in human population and concern for food security leads to a demand for increased food production, which must be sustainable and not degrade the natural resources on which agriculture depends.

Photosynthesis

Light energy is absorbed by photosynthetic pigments to generate ATP and for photolysis.

Inbreeding

Selected related plants or animals are bred for several generations until the population breeds true to the desired type due to the elimination of heterozygotes.

Inbreeding depression

A result of inbreeding that can be an increase in the frequency of individuals who are homozygous for recessive deleterious alleles, resulting in reduced survival and reproduction.

Cross breeding

Individuals from different breeds may produce a new crossbreed population with improved characteristics.

F1 hybrids

F1 hybrids, produced by the crossing of two different inbred lines, create a relatively uniform heterozygous crop and often have increased vigour and yield.

Weeds, pests and diseases

Compete with crop plants, while other pests and diseases damage crop plants, all of which reduce productivity.

Symbiosis

Co-evolved intimate relationships between members of two different species.

Parasite

Benefits in terms of energy or nutrients, whereas its host is harmed by the loss of these resources.

Mutualism

Both mutualistic partner species benefit in an interdependent relationship.

Altruistic behaviour

Harms the donor individual but benefits the recipient.

Kin selection

The donor will benefit in terms of the increased chances of survival of shared genes in the recipient’s offspring or future offspring.

Components of biodiversity

Genetic diversity, species diversity and ecosystem diversity.

Genetic diversity

Is the number and frequency of all the alleles within a population.

Species diversity

Comprises the number of different species in an ecosystem (the species richness) and the proportion of each species in the ecosystem (the relative abundance).

Ecosystem diversity

Refers to the number of distinct ecosystems within a defined area.

Bottleneck effect

Small populations may lose the genetic variation necessary to enable evolutionary responses to environmental change.

Naturalised species

Those that become established within wild communities.

Invasive species

Naturalised species that spread rapidly and eliminate native species therefore reducing species diversity.