DNA Basics
What molecule carries the genetic instructions for all living organisms?
DNA
What is a small section of DNA that contains instructions for a trait called?
Gene
What do you call the observable traits of an organism, such as eye colour or freckles?
Phenotype
What type of letter is usually used to represent dominant alleles?
Capitial letter
What are the building blocks of DNA called?
Nucleotides
Which part of the cell contains most of the DNA?
The nucleus
What structures is DNA packed into inside the nucleus?
Chromosomes
What term describes the genetic combination of alleles an organism has?
Genotype
What type of letter is usually used to represent recessive alleles?
Lowercase letter
What component of a nucleotide contains A, T, C, or G?
Nitrogen base
What is the twisted ladder shape of DNA called?
Double helix
How many pairs of chromosomes do humans have?
23
What do you call a genotype that has two identical alleles?
Homozygous
What type of genotype is bb?
Homozygous recessive
Which DNA base pairs with adenine?
Thymine
What are the four nitrogen bases found in DNA?
Adenine, Thymine, Cytosine, Guanine
What are different versions of the same gene called?
Alleles
What do you call a genotype that has two different alleles?
Heterozygous
What type of genotype is Bb?
Heterozygous
Which DNA base pairs with cytosine?
Guanine
What two components form the backbone of the DNA molecule?
Deoxyribose sugar and phosphate
What is the process called when DNA copies itself before cell division?
DNA replication
Which trait appears when both a dominant and recessive allele are present?
Dominant trait
If B = brown eyes and b = blue eyes, which genotype will produce blue eyes?
bb
What type of bond holds the nitrogen bases together in DNA?
Hydrogen bonds