Anatomy and Physiology Exam 2

genetics

study of the inheritance of characteristics

genes

DNA sequences that encode specific proteins

genome

a complete set of genetic instructions in a person’s cells

DNA

consists of a sequence of nucleotide building blocks A, G, C, and T

What percent of human genomes are alike in their DNA sequence?

>99.9%

Karyotype

chart displaying 23 chromosome pairs in size order

Autosomes

pairs 1-22, determine traits but not sex

Sex chromosomes

pair 23, determines sex

How many copies do human cells have of each chromosome? What about genes?

2 copies of each chromosome; 2 copies of each gene

Genetic traits

genes that code for a particular trait

If the alleles for each gene are identical….

homozygous trait

If the alleles for each gene are different….

heterozygous trait

Genotype

particular combination of alleles for a particular gene or genes

Phenotype

appearance of a trait or health condition that develops as a result of the ways the genes are expressed

What are the two types of alleles?

dominant and recessive

dominant

allele that masks expression of recessive allele, when present in a heterozygote

recessive

allele that may be masked by dominant gene, when present in a heterozygote

Mendelian inheritance

inheritance in which traits are regulated in dominant/ recessive manner

What is determined by dominant allele

phenotype of a heterozygote

Punnett Square

table used to predict probabilities of genotypes in offspring for certain traits

chromosomal inheritance

inheritance of a trait through entire chromosomes

Sex/gender is a trait inherited by….

inheritance of x and Y chromosomes

In sex-linked traits, males carry only one X chromosome, so they exhibit….

recessive x-linked traits more frequently than females

How many chromosomes do humans have?

46