Genetics Flashcards
What is genetics?
- It is the study of heredity and the variation of inherited characteristics.
-The study of genes and how traits are passed down through generations.
What are the four foundation blocks of an organism?
- A cell: the simplest unit of life.
- A tissue: a group of cells that work together to perform a specific functions.
- An organ: form systèmes when they work together.
- An organism: form an organism when they work together.
What is a gene?
-It is a sequence of DNA which encodes the amino acid sequence of a polypeptide.
How many genes does a human have on average?
-21,000 genes
What is a chromosome?
- A chromosome is a thread like structure which carries our DNA.
- A chromosome is made of DNA and proteins.
- DNA is coiled tightly around histones.
What do you call a humans complete set of chromosomes and how many pairs do we have?
- karyotype.
- 23 pairs
What is one half of a chromosome known as?
- A chromatid.
What joins two chromatids together and what is it?
- A centromere joins two chromatids together.
- Spindle fibres attach themselves to the centromere during cell division.
What is a telomere and where are they located?
- They are short DNA sequences and they are located at the ends of chromosomes.
What makes up chromosomes?
- Chromosomes consist of DNA, proteins and a small amount of RNA.
What re the three types of proteins found in chromosomes?
- Histones
- Non-histones
- Actin-histones
What is a nucleosome?
- It is a structural unit of a chromosome.
- DNA coiled around a core of histones and chromatin.
What is a metacentric chromosome?
The centromere is located in the middle of the chromosome; all arms are equal length.
What is a submetacentric chromosome?
The centromere is located on the chromosome and it results in one arm being longer than the other.
What is an acrocentric chromosome?
The centromere is located at the near end of the chromosome and resulting in one arm being a lot longer compared to the other one.
What is an telocentric chromosome?
The centromere is located at the very end of the chromosome and they are considered to be unstable and they can break easily.
What is Ploidy?
- It is the number of complete sets of chromosomes in a cell.
What is polyploidy?
- When individuals have extra complete sets of chromosomes.
What is genotype?
- An individuals unique sequence of DNA.
What is phenotype?
- Any characteristics which can be shown to be inherited.
- An example is eye colour.
How can dominant and recessive traits be shown.
Dominant= AA, trait is always expresses
Recessive= aa, trait is masked
What is the difference between homozygous and heterozygous individuals?
- Homozygous individuals carry the same alleles.
- heterozygous individuals carry different alleles.
What is an allele?
Two or more forms of a gene and can be found at the same place of the chromosome.
What is co-dominance?
- When two alleles are expressed equally in a phenotype of an individual.
