Year 10 Biology Flashcards
Where is the DNA located in the Cell?
In the Nucleus of the cell
How is DNA organized in the Nucleus?
DNA is organized into genes that are found on Chromosomes
What is a Gene
Genes are a segment of DNA that codes for a particular protein. e.g. eye colour
How many pairs of chromosomes do humans have?
23 Pairs
How many chromosomes do humans have in total?
46 in total
What does diploid mean?
A paired set of chromosomes in somatic cells
What is a somatic cell?
The cells of the body except sex cells
What are gametes?
Reproduction or sex cells (sperm or over)
What does Haploid mean?
The possession of one copy of each chromosome in a cell
What sex chromosomes do females have?
Sex chromosomes XX
What sex chromosomes do males have?
Sex Chromosomes XY
What is an autosome?
Any chromosome not involved in sex determination
What is a sex chromosome?
The chromosomes that determine an individuals sex
What are the building blocks of DNA?
Nucleotides
What are the components of a nucleotide?
Phosphate group, pentose sugar, and nitrogenous base.
What components form the DNA backbone?
Sugar and Phosphate
What components form the rungs in DNA
Nitrogenous Bases
What are the 4 types of nitrogenous bases?
Adenine, thymine, cytosine, and guanine
What is complementary base pairing?
Each base will only bond with one other specific base
Why does DNA have a double Helix?
All of these combined form it.
What is an Allele?
Different versions of a gene.
What is the difference between a gene and an allele?
Genes specify traits, alleles specify the form a gene takes.
What are dominant Alleles?
Will always be expressed when they’re present.
What are recessive alleles?
Expressed only when there are 2 recessive alleles?
What is a genotype?
Alleles that a person has.
What is a phenotype?
The trait that is seen.
What does homozygous mean?
The same allele.
What does heterozygous mean?
Different alleles.
What is a genetic cross?
Genetic Crosses measure the probability of all outcomes for a specific genetic cross.
What’s a punnet square?
A punnet square is the tool we used to do a cross.
How to complete a punnet square?
- Designate characters to represent alleles
- Write the genotype or phenotype of the parents.
- Use the grid to work out gamete combinations.
- Write the genotype and phenotype ratio of offspring.
