B12 Reproduction Flashcards
What is asexual reproduction
Asexual reproduction only involves one parent so there is no joining of sex cells during fertilisation.
What is sexual reproduction
The formation of a new organism by combining the genetic material of two organisms.
How many cells does the body have?
46
What is meisois
Meiosis is the type of cell division that produces gametes . A human body cell contains 46 chromosomes arranged in 23 pairs.
What are gametes
Sex cells are also known as gametes. Male gametes are made by male reproductive structures. Female gametes are made by female reproductive structures. A gamete contains a single set of chromosomes in its nucleus and is said to be haploid .
What is variation
Difference between individual organisms
Phenotype
The physical appearance/biochemistry of an individual for a particular characteristic
Genotype
The genetic make up of an individual for a particular characteristic, for example hair or eye colour
Gene
The basic unit of genetic material inherited from our parents. A gene is a section of a DNA which controls part of a cell’s chemistry – particular protein production
Allele
Different form of the same gene sometimes referred to as variants
Dominant
The phenotype will be apparent in the offspring even if only one of the alleles is inherited
Recessive
A phenotype that will only show up in the offspring if both of the alleles coding for that characteristic are inhertited
Homozygous
Individual with identical alleles for a characteristic
Heterozygous
Individual with different alleles for characteristic
What is fertilisation
Fertilisation is the fusion of the nucleus of a male gamete with the nucleus of a female gamete, producing a new cell called a zygote .
How are gametes formed
Cells in the reproductive organs divide them meiosis to form the gametes
What is the process of meiosis
The genetic material is copied and then the cells divides twice to form for gametes each with a single set of chromosomes
Where do you gametes join
Gametes join at fertilisation to restore the normal number of chromosomes. The new cell divides by mitosis. The number of cells increase and as the embryo develops, the cells differentiate
What is a human genome
The genome of an organism is the entire genetic material of that organism
What is DNA
The genetic material in the nucleus of a cell is composed of DNA. DNA is a polymer made up of two strands forming a double helix
What is a Punnett Square
A way of modelling a genetic cross and predicting the outcome using probability
Sex Chromosome
Carry the information that determines the sex of an individual
Polydactyl
Polydactyly is a dominant phenotype caused by a dominant allele which can be inherited from either or both parents
What is cystic fibrosis
Cystic fibrosis is a recessive phenotype and is caused by recessive alleles which must be inherited from both parents
What are carriers
Individuals who are heterozygous for a recessive allele linked to a genetic disorder. Carriers have one healthy are you so they are not affected themselves but they can pass on the affected allele to their offspring
Haploid
Cells contain one version of each chromosome
Diploid
Cells contain pairs of chromosomes
Zygote
When gametes fuse they create a diploid cell
