1.3 Exam Prep Flashcards
To prepare
The different alleles in a population
Variation
The physical expression of a trait
Phenotype
The combinations of alleles that an organism possesses. Represented with capital letters for dominant, and lowercase for recessive.
Genotype
A double-stranded molecule which is made up of nucleotides. This stores the genetic information made to produce the organism.
DNA
DNA is made up of these bonded together. These are made up of a phosphate, sugar, and a base
Nucleotides
This is a long, thread-like structure made of DNA and proteins that contains genetic information. It helps to organize and protect the DNA, ensuring that genes are passed on during cell division. Humans typically have 46 chromosomes, arranged in 23 pairs.
Chromosome
GeneA small strand of DNA which codes for a certain trait.
Gene
Where a gene is located on a chromosome
Loci
An alternate form of a geneAllele
Allele
Two chromosomes with the same genes (one from the sperm, one from the egg) but with potentially different alleles.
Homologous Pair
The order of the bases (A,T,C,G) in an allele
Base sequence
Permanent change in the DNA base sequence
Mutation
Something which causes a mutation
Mutagen
A change in the base sequence that doesn’t change the amino acid sequence, so it doesn’t change the protein.
Silent Mutation
A permanent change in the DNA base sequence gives the organism a mutation, making survival easier.
Beneficial Mutation
A permanent change in the DNA base sequence gives the organism a mutation making survival more difficult.
Harmful Mutation
A mutation that is not in a gamete so it cannot be passed down to offspring (meaning it’s somatic)
Non-inherited mutation
A cell which isn’t a gamete (sex cell)
A cell which isn’t a gamete (sex cell)
A genetically unique sperm fertilizes a genetically unique egg and produces offspring which has a combination of alleles, different from both parents.
Sexual Reproduction
Where a haploid sperm and haploid egg fuse together to create a zygote.
Fertilisation
An organism or cell having only one complete set of chromosomes
Haploid
A cell having two sets of chromosomes (one from each parent)
Diploid
A sex cell such as an egg or sperm which unite during sexual reproduction to produce a zygote.
Gamete
A fertilised egg
Zygote
A type of cell division that results in four haploid daughter gametes, each genetically different from each other
Meiosis
Exchange of alleles between homologous chromosomes during meiosis. This results in recombined chromosomes with some alleles from the mother and some from the father.
Crossing over
When homologous chromosomes line up independently, they create a random order of maternal/paternal chromosomes in the gametes.
Independent Assortment
Allele pairs are separated during meiosis so each gamete has only 1 instead of 2 alleles for a trait
Segregation
Two of the same alleles for a trait
Homozygous
Two different alleles for a trait
Heterozygous
An allele that is always shown in the phenotype, which masks the recessive allele.
Dominant allele
Alleles will only appear in the phenotype when dominant alleles are absent.
Recessive Allele
A tool used to predict inheritance
Punnet Squares
Compares something to another
Ratios
A tool to show the inheritance of a trait across generations
Pedigree charts
When humans decide which individuals breed together
Selective Breeding
Individuals with the best alleles in the given environment will survive to reproduce and pass the alleles on. These alleles will then become more common, and those with less-suited alleles are less likely to survive, making the alleles rarer.
Natural Selection
Being able to find food and resources to live as long as they can
Survival
Something new in the environment (e.g. predator, disease) that influences if certain individuals live or die.
Environmental Change
Closely related individuals having offspring
Inbreeding
A reduction in the ability to survive and reproduce due to inbreeding, as well as reduced variation.
Inbreeding depression
Figuring out what the sequence of bases is for a gene.
DNA Sequencing
Testing an individual to see if they have a specific sequence of bases (or genes)
DNA screening
Matching an individual’s genetic markers to another individual to see how they are related to each other.
DNA profiling
Using a genetic marker/base sequence/gene that only occurs in one species to see whether an unknown individual is that species or not.
DNA barcoding
