mendel Flashcards
(31 cards)
What is a cell?
The basic unit of all living things.
what is the nucleus, what does it do and where is it found?
The ‘control centre’ of the cell found in all eukaryote cells. It contains the instructions for the metabolism of the cell, its growth and division – place where the codes to build proteins (genes) is located
what is a chromosome
A strand of DNA, found in all living things, usually in the nucleus. All species have different numbers of chromosomes.
what is DNA?
a self-replicating material that is present in nearly all living organisms as the main constituent of chromosomes. It is the carrier of genetic information
what is autosomes?
Chromosome not involved in sex determination. Humans have two copies of each of the 22 different types of autosomes (44 in total)
what is a sex chromosome?
Chromosomes involved in the determination of sex. Humans have two of these – one large chromosome X and a smaller Y. Normal females have two X chromosomes, a normal male has an X and Y.
what is a karyotype?
A photo of the chromosomes in an individual where maternal and paternal chromosomes have been paired and arranged from largest to smallest – together with the sex chromosomes
what is a homolygous chromosome?
A pair of matching (size, staining pattern, location of centromere) chromosomes containing the same genes, one of maternal origin and one of paternal origin.
what is a somatic cell?
Body cell, contains two sets of each chromosome (one maternal and one paternal)
what is mitosis?
Cell division in somatic cells for growth and repair. One diploid parent cell produces two identical diploid daughter cells.
what is a diploid?
Two sets of chromosomes – one maternal one paternal in origin.
what is meiosis?
Cell division in gonads to produce gametes. One diploid parent cell produces four non-identical haploid daughter cells called gametes – for reproduction.
what is a gonad?
A general term for ovaries (female) and testes (male).
what is a gamete?
A general name for ova or egg (female) and sperm (male).
what is a haploid?
One complete set of chromosomes. Gametes are the only haploid cells in humans.
what is a zygote?
A new cell produced by the fusion of ovum and sperm cells (fertilisation)
what is a gene?
A section of DNA along a chromosome which codes for one inherited trait (protein). A gene is found on a particular chromosome at a particular place or locus.
what is an allele?
One version or variety of a gene. One gene can have a number of different alleles which may exist at the same locus. Each individual carries 2 copies of each autosome and so 2 alleles – which may be the same or different. A gene located on the X chromosome is not found on the Y; therefore males only get one allele for an X-linked gene.
what is a genotype?
The actual set of alleles for a gene present in an individual
what is a phenotype?
The outward, physical expression of an individual – it is the end result of the interaction between the genotype and the environment
what is an environment?
All factors affecting the growth and life of an individual – nutrition, light etc.
what is a homozygous, give an example
Both alleles for the genotype are identical. E.g. AA or aa
what is hetrozygous, give an example
Both alleles in the genotype are different. E.g. Aa
what is a dominant allele?
A trait that is always expressed in the phenotype regardless if the individual is homozygous or heterozygous for a trait. Denoted by a capital letter in the genotype.
