science biology ae year 10 Flashcards
Defintions
DNA
The molecule that determines the characteristics of most living things
Gene
A section of DNA that expresses certain traits
Chromosome
A long DNA molecule wrapped around proteins
Sex chromosomes
Are chromosomes that carry the genes that determine the sex of an individual
Sex chromosomes in Male
Males have one x and one y chromosomes
Haploid
Is a cell that contains only one set of chromosomes
Diploid
a cell that contains two sets of chromosomes
Homologous
Are chromosomes that contain alleles of the same genotype
Non-Homologous
Are chromosomes that contain alleles of different gene types
Karyotype
Is an individual’s complete set of chromosomes
Nucleotide
Nucleotides are used to create DNA and RNA
Base Pairing Rule
Is a set of rules for the regulated form of base pairing between one purine (A,G) and one pyrimidine (T,C)
What are the 4 nitrogenous bases
Adenine, Thymine, Cytosine, Guanine
Triplet
A sequence of three nucleotides that determines one amino acid
RNA
Partial copies of DNA that look similar but are shorter and missing one side of the helix
Telomere
Are structures made from DNA sequences and proteins found at the ends of chromosomes
Gametes (sex cells)
Are an organism’s reproductive cell
Somatic cells
The cells in the body except the egg and sperm cells
Autosomes
Any chromosome that is not a sex chromosome (22 pairs)
Sex chromosomes in female
Females have two x chromosomes
Mitosis
The process of making new body cells
Meiosis
Is the type of cell division that creates egg and sperm cells into two new cells
Cytokinesis
The process in which the cytoplasm of the cell is divided
Crossing over
the exchange of DNA between paired homologous chromosomes during meiosis
Fertilization
The process by which two gametes fuse to become a zygote developing into new organisms.
Identical twins
Occurs when a single egg cell is fertilized by a single sperm cell and the zygote splits into two
Fraternal Twins
When two separate eggs are fertilised by two separate sperm
Inheritance
The process of transmission of genes from parent to offspring
Genotype
The genetic makeup of an organism
Phenotype
An individual’s observable traits
Allele
One of two or more versions of a genetic sequences at a particular region on a chromosome
dominant Gene
The relation ship between two versions of a gene that overpowers the other
Recessive gene
A trait that is expressed only when a genotype is homozygous
Homozygous
You inherit the same version of the gene from each parent. Two matching genes
Heterozygous
You inherit a different version of a gene from each parent
Pure Breeding
When self fertilized, produces offspring with the same observable traits
Hybrid
An offspring of two animals or plants of different species
Carrier
A person who can pass an inherited genetic/disease on to their children but who does not have the disease
Complete dominance
a condition where in the dominant allele completely masks the effect on the recessive allele
Gregor mendel
Discovered the fundamental laws of inheritance
Number of chromosomes in a body cell (somatic cell)
46 chromosomes
Number of chromosomes in a gamete (sex cell)
2 chromosomes
Punnet Sqaure
A table in which all of the possible outcomes for a genetic cross between two individuals when known genotypes are given
Pedigree
A chart that diagrams the inheritance of a trait or health condition through generations of a family
Monosomy
The condition in which only one chromosome from a pair is present in cells rather than the two copies usually found in diploid cells
Trisomy
A deviation in chromosome number
