Biology Definitions Flashcards
Describe the role of DNA in organisms
DNA is the genetic code that makes up every aspect of the human body e.g. hair color
Distinguish between somatic cells and gametes
Gametes are sex cells and they only have 23 chromosomes (produced by meiosis), whereas somatic cells are not sex cells and they have 46 chromosomes (produced by mitosis)
How do you distinguish between a male and female only using chromosomes
Males have an x and a y chromosome whereas females have two x chromosomes.
Distinguish between monosomy and trisomy
Trisomy is when a person has an extra chromosome most commonly found in the 21st pair whereas monosomy is when a person has an extra sex chromosome only found in the 23rd pair.
What is a protein?
Proteins are biomolecules that are composed of smaller building blocks called amino acids.
Describe how gene mutations occur
Nucleotide is swapped, added or deleted in a gene. Chromosomes can have sections removed, swapped around or extra or missing chromosomes in cells.
Distinguish between induced and spontaneous mutations
Spontaneous mutations occur due to errors in DNA repletion when the cell is divided. Induced mutations occur due to exposure to mutagens e.g. chemicals, radiation or viruses.
Define mutagen
They are agents that damage the structure of DNA altering the nucleotide sequence of a gene causing causing gene mutation.
Explain the cause of a sickle cells anaemia and how this disease affects humans.
It is an inherited disease caused by a defect in a gene. It causes damage to the nerves and organs, can become fatal.
Describe what a Codon is
A codon is a sequence of three nucleotides in mRNA that codes for an amino acid or serves as start/stop signals during protein synthesis.
Contrast RNA and DNA
RNA is single-stranded with ribose sugar and uses uracil instead of thymine, while DNA is double-stranded with deoxyribose sugar. RNA functions in protein synthesis and gene regulation, whereas DNA serves as the long-term storage molecule for genetic information within cells.
Differentiate between genes and alleles
A gene is a particular section of DNA, allele is the specific type of gene e.g. hair colour
Differentiate between natural selection and selective breeding
Natural selection is driven by environmental pressures that favor traits aiding survival, while selective breeding is human-guided to enhance specific desired traits in organisms.
Describe biodiversity
Biodiversity refers to the variety and variability of life on Earth, encompassing the different species, ecosystems, and genetic differences within species.
Differentiate between genotype and phenotype
Genotype refers to the genetic makeup of an organism, while phenotype is the observable physical and behavioral traits resulting from the interaction of the genotype with the environment.
