definitions Flashcards
Sexual reproduction
Genetic information comes from two sexes, and gametes must meet and fuse
Asexual reproduction
Doesn’t require an egg and sperm (gametes) to meet, and usually comes from one organism
Gamete
Gametes are cells which can give rise to a new organism when they meet with a gamete of the opposite gender.
External fertilisation
Egg and sperm meet outside the female body
Internal fertilisation
Egg and sperm meet inside the female body
Binary fission
Type of asexual reproduction where bacteria ‘split’ in half, each half becomes a new daughter cell
Budding
Type of yeast asexual reproduction where cells grow bigger until a little ‘bud’ forms on the mother cell. This bud grows bigger until it is big enough to break off.
Mitosis
the process by which a cell replicates its chromosomes and then segregates them, producing two identical nuclei in preparation for cell division.
Meiosis
Meiosis is a process where a single cell divides twice to produce four cells containing half the original amount of genetic information.
DNA replication
Making new copies of DNA so new cells can have a copy
Transcription
The process of copying information encoded in DNA into a ‘photocopy’ or RNA so the ribosome can read it
Translation
Ribosome ‘reading’ the mRNA which tells it to recruit certain amino acids. Results in a polypeptide chain
Polypeptides
Polypeptides are short proteins made up of chains of amino acids
Chromosome
a long DNA molecule with part or all of the genetic material of an organism.
Gene
A gene codes for a particular characteristic. A gene is a section of our DNA molecule
Allele
Allele is a form of a gene. For each gene, we have two alleles - one from mum and one from dad
Phenotype
This is the physical characteristic of a genotype
Genotype
the genetic makeup of an organism
Homozygous genotypes
Genotypes where the two alleles are the same
Heterozygous genotypes
Genotypes where the two alleles are different
Simple dominance
Where one allele is completely dominant over the other (the recessive allele)
Monohybrid cross
A Medelian cross where the two individuals have the same genotype
Co-dominance
Where two or more alleles have equal dominance (which gives rise to a third outcome)
Sex-linked genes
to characteristics (or traits) that are influenced by genes carried on the sex chromosomes.
Single nucleotide polymorphism (SNP)
A common genetic variation that occurs in >1% of the population
DNA sequencing
Finding out what the sequence of DNA is
Mutagen
Anything causing mutations
Mutation
A change in DNA sequence
Genetic flow/gene mutation
Introducing genes of one population into another by breeding between two populations
Genetic diversity
total number of genetic characteristics in the genetic makeup of a species
Biotechnology
the use of biological processes for a purpose, especially the genetic manipulation of microorganisms for the production of antibiotics, hormones, etc.
Artificial insemination
Taking semen from a male animal and inserting it into a female uterus
Cloning
Creating a genetically identical copy of an organism
Transgenic organisms
Species that are the result of genetic modification
Pathogen
A foreign body that can cause disease
Antigen
Molecules made of protein that trigger the immune response when they detect infectious pathogens
Antibody
Made by plasma cells which specifically target a pathogen by binding to it
Epidemic
An infectious disease spreading across a wide range
Innate immune system
the first response of the body’s immune system to a harmful foreign substance
Adaptive immune system
Made up of T cells and B cells and can eliminate or prevent the growth of pathogens
Cytokines
Proteins that immune cells use to communicate with each other
Cell differentiation
How cells become specialised for their different functions. They all start off exactly the same
Quarantine
a restriction on the movement of people, animals and goods which is intended to prevent the spread of disease or pests.
Passive immunity
Injection of someone else’s antibodies
Active immunity
Making your own antibodies in response to the presence of an antigen
Homeostasis
the state of steady internal, physical, and chemical conditions maintained by living systems.
Enzymes
proteins that help speed up metabolism, or the chemical reactions in our bodies.
Substrates
Molecules part of a chemical reaction which react together to form the products
Optimal
Best for efficiency of a reaction
Endotherm organisms
Organisms which control their own body temperature, independently of the outside environment
Ectotherm
Organisms which do not control their own body temperature, and rely on the outside environment
Adaptive advantage
An advantage of a particular characteristic which helps the organism to adapt to the environment, according to the theory of evolution by natural selection
Hormones
Chemicals which are used to control organs in the body
Disease
Disturbance in normal structure and function caused by something outside the body
Disorder
Disturbance in normal body structure and function caused by something inside the body
Cancer
Uncontrolled growth of cells
Incidence
How many new cases of this disease in x time?
Prevalence
How many people have had this disease in x time?
Mortality
Number of deaths in a given time or location
Epidemiology
The study of how a disease occurs and spreads and where it is most prevalent
Genetic engineering
Changing the characteristics of an organism by changing its genes
