B5

• what is a gamete

  sex cell
• what is a chromosome

  a threadlike structure of nucleic acids and protein found in the nucleus of most living cells, carrying genetic information in the form of genes
• what is a gene

  segment of DNA that codes for a protein
• what is an allele

  one of two or more alternative forms of a gene that arise by mutation and are found at the same place on a chromosome
• what does dominant mean

  that that gene will be expressed
• what does recessive mean

  that is won't be expessed unless both alleles are recessive
• what does homozygous mean

  It means you have the defective gene from both parents.
• what does heterozygous mean

  It means you only have 1 defective gene from 1 parent
• what is a genotype

  genetic makeup of an individual
• what is a phenotype

  physical appearance
• what is a genome

  The entire set of genetic material in an organism
• what is nature nurture

  Nature has to do with genetics, while nurture has to do with environment, family, friends, etc
• what is discontinuous variation

  A characteristic that can only result in certain values e.g eye colour
• what is continuous variation

  Continuous variation is where a characteristic can have any value over a range, from minimum to maximum e.g height
• what do variants arise from

  mutations
• how do mutations affect phenotype

  -most have no affect

  -some influence

  -very rarely determine
• how do genetic variants affect phenotype

  -in coding DNA by altering activity of a protein

  -non-coding DNA by altering how genes are expressed

  -mutations affecting protein structure and active sites of enzymes

  -stopping transcription of MRNA
• what are advantages of asexual reproduction

  Identical offspring

  -no special cells required

  -speedy process

  -lots of offspring

  -don't need a mate
• what are disadvantages of asexual reproduction

  no genetic variation
• what are advantages of sexual reproduction

  -Diverse offspring

  -adaptability

  -can live in different environments
• what are disadvantages of sexual reproduction

  - slow reproductive rate

  - smaller number of offspring

  - more energy needed
• what is haploid

  one set of chromosomes
• what is diploid

  2 sets of chromosomes
• what is meiotic cell division

  A form of cell division that includes only one round of DNA replication but two rounds of nuclear division; meiotic cell division makes sexual reproduction possible
• what is single gene inheritance

  when a characteristic is controlled by a single gene
• what is a Punnett square


  A chart that shows all the possible combinations of alleles that can result from a genetic cross
• how is sex determined in humans

  The sex chromosomes determine whether you are female (XX) or male (XY)
• who is Mendel

  Father of genetics
• what did Mendel do

  Mendel developed a method where he could cross-pollinate pea plants. Through working in the garden, he discovered the meaning behind genetics
• what is the genetic variation like in a population of species

  very diverse
• what are natural classification systems

  based on the relationship between the common ancestor and descendants
• what are artificial classification systems

  based purely on observations
• what is molecular phylogenetics

  When there aren't enough homologous traits to compare, we look at molecular sequence data such as DNA
• what is evolution

  the process of change over time
• how does evolution occur

  through natural selection
• what is natural selection

  the process whereby organisms better adapted to their environment tend to survive and produce more offspring
• what is mutation

  any change in the DNA sequence
• what is the evidence for evolution

  Fossils and antibiotic resistance in bacteria
• what was the work of Darwin

  his investigation into Finches and their different beaks based on what they ate
• what is a store of biodiversity

  seedbanks