Skyence flashing cards

trait

physical characteristic

heredity

passing of traits from parent to offspring

purebred

always produces offspring with the same form of a trait as the parent

gene

a a segment of DNA that controls a trait

allele

possible forms of a trait. Ex: allele for eye color

dominant allele

trait always shows up in the organism when the allele is present

recessive allele

is masked, or covered up, whenever the dominant allele is present. A trait controlled by the recessive allele will only show up when the dominant allele is not present.

hybrid

of mixed character-- mixed parts (alleles)

probability

likelihood that a particular event will occur

Punnett square

A chart that shows all the possible combinations of alleles that can result from a genetic cross

phenotype

the physical appearance of an organism (what you see)

genotype

genetic make-up, or allele combinations (code)

homozygous

uniform; two identical alleles for a trait; the same throughout

heterozygous

possessing two different alleles for a trait, or gene, such as Tt

codominance

alleles are neither dominant nor recessive -- both are independently expressed (color patches, stripes)

incomplete dominance

alleles are neither dominant nor recessive-- both are expressed, but result in a blend of sorts-- black and white alleles are expressed as gray, or red and white expressed as pink

chromosome

A threadlike, gene-carrying structure found in the nucleus. Each one consists of one very long DNA molecule and its associated proteins.

mutation

change in a DNA sequence that affects genetic information

point mutation

gene mutation in which a single base pair in DNA has been changed

deletion mutation

a mutation in which one or more pairs of nucleotides are removed from a gene

insertion mutation

a mutation in which one or more nucleotides are added to a gene

frameshift mutation

mutation that shifts the "reading" frame of the codons in a "genetic message" by inserting or deleting a nucleotide

codon

A specific sequence of three adjacent bases on a strand of DNA or RNA that provides genetic code information for a particular amino acid

total number of chromosomes in the human genome

46

humans have ____ chromosome pairs

23

Punnett Square

A chart that shows all the possible combinations of alleles that can result from a genetic cross

probability

A number that describes how likely it is that an event will occur

Adenine pairs with thymine and guanine pairs with cytosine

Thymine

guanine pairs with

cytosine

nitrogenous bases

adenine, thymine, cytosine, guanine

dominant and recessive model of inheritance

an introduction to genetics; in reality inheritance patterns are more complicated but this is a good entry point from which to learn