Genetics Flashcards
(35 cards)
What is a genotype?
An individuals genetic makeup that contains the specific combinations of alleles within the genes of an organism
Genotypes are the alleles that determine the phenotype
What is a phenotype?
The observable expression of a persons genetics
often expressed as traits such as hair, eye, skin
What is a karyotype?
The entirety of an organisms Chromosomes in a visual representation
Describe an allele
An allele is a variation of a specific gene
alleles are either dominant, recessive or co-dominant
What are genomes ?
An organisms complete set of genetic material, which includes all of the genes. It is essential for the information that controls growth, development, function and reproduction
Discuss heterozygous and homozygous in genetics
A heterozygous individual has multiple differently expressed alleles e.g. Aa whereas a homozygous individual has identical alleles e.g. aa
What are the 5 nucleotides and the base pairs
Uracil
Thymine
Adenine
Guanine
Cytosine
DNA
C <-> G
T <-> A
in RNA there is a U <-> A paring as U replaces T
Differentiate between RNA and DNA
DNA is a double stranded molecule - RNA is a single stranded molecule
DNA contains deoxyribose as the sugar component - RNA contains ribose as the sugar
DNA has the nitrogenous bases Adenine, Cytosine, Guanine and Thymine - RNA has Adenine, Cytosine, Guanine and Uracil
DNA is usually longer than RNA
DNA carries the genetic information and instructions for the synthesis of RNA and proteins
RNA has 3 main types messenger mRNA, transfer tRNA and ribosomal rRNA
DNA is located only in the nucleus whilst RNA is located in the cytoplasm and nucleus
DNA is more stable than RNA
Describe the process of mitosis
MITOSIS IN MY TOE
Mitosis occurs as a cell division process that produce 2 identical diploid daughter cells
Mitosis contains only 1 round of division
Describe the process of meiosis
MEIOSIS CREATED ME
The division of specialised gametes and only occurs in reproductive cells
Meiosis contains 2 rounds of specialised division to produce 4 daughter cells
How are mitosis and meiosis different?
Mitosis is responsible for the production of genetically identical diploid cells and meiosis is responsible for the generation of genetically diverse haploid gametes as part of sexual reproduction
what are the stages of a cell life cycle?
Summarise recessive and dominant alleles
What is a genetic pedigree?
A graphical representation of heredity within a family. It represents the genetic history and the inheritance of specific traits or genes that can be passed across multiple generations. They are largely used to assess the possible risk of a person inheriting a gene as well as identify patterns of inheritance
What is a sex linked trait?
A sex-linked trait is an expression of a gene on the X or Y chromosomes of an individual
Why do sex linked traits or conditions present in males more than females
Sex linked traits will affect males more than females due to males having only one X and one Y chromosome, making them hemizygous for X linked genes (having only 1 set of alleles in an organism with 2 chromosomes in the set).
How many chromosomes are there?
23 pairs of 46 chromosomes
What is a phenotype ratio?
Differentiate a gene and an allele
A gene is the “master copy” that will code for a specific trait, and an allele is the genetic expression of the trait. E.g. MC1R is the gene for hair colour, however the allele can be expressed as red, brown, blonde, black etc.
What is the functional unit of heredity?
A gene
What is Mendel’s first law of inheritance ?
LAW OF SEGREGATION
an individuals 2 alleles for a given trait will separate during the formation of gametes. Each gamete will only contain one of the two alleles for a given trait, which is why offspring only inherit 1 allele from each parent for a gene.
What is a genetic mutation?
A permanent alteration within the DNA sequence of the genome. It can result from changes to the nucleotide bases, deletion or insertion of genetic material or a large structural change to the DNA. Mutations can lead to a variation in the organism’s traits or development of diseases.
What is a Punnett square, how is it used?
Named after geneticist Reginald Punnett, it is a graphical tool used to predict the possible combinations of alleles that an offspring can inherit from the parents, focusing on the dominances and or recession of a trait.
TO USE THE TOOL - alleles from parent 1 are written on the top and alleles from parent 2 are written on the side. The squares are then filled with the different combination of alleles.
Define a genetic carrier?
An individual who carries the recessive allele for a genetic trait or condition. As this trait is recessive, it often does not manifest the trait that is associated, however the gene is passed onto the individuals offspring.
The trait would show in future generations if the other parent also carries the recessive allele of that trait. This gives the offspring 2 alleles for this trait, increasing the risk of expression.
