B12 reproduction Flashcards
what is sexual reproduction
involves the joining (fusion) of male and female gametes
sperm and egg cells in animals
pollen and egg cells in flowering plants
why is there variation in sexual reproduction
In sexual reproduction there is mixing of genetic information which
leads to variety in the offspring. The formation of gametes involves meiosis
what is asexual reproduction
only involves one parent
no fusion of gametes or mixing of genetic material
genetically identical offspring (mitosis)
what happens when a cell divides by mitosis
copies of genetic information are made
cell divides twice to form four gametes
all gametes are genetically different from each other
why is meiosis important
halves the number of chromosomes in gametes meaning fertilisation can restore the full number of chromosomes
what is DNA
a polymer made up of two strands forming a double helix
where is DNA found
chromosomes
what is a gene
a small section of DNA on a chromosome
each gene codes for a particular sequence of amino acids to make a specific protein
what is a genome
the entire genetic material of that organism
what are the important uses of genomes in the future
search for genes linked to different types of disease
understanding and treatment of inherited disorders
use in tracing human migration patterns from the past
what is a gamete
a specialised sex cell formed by meiosis
what are chromosomes
long molecules found in the nucleus of all cells made by DNA
what is an allele
an alternative form of a particular gene
what is the genotype
the combination of alleles present in the gene
what is the phenotype
how the allele is expressed e.g blue eyes
