Exam 1 ISU Bsc 101 Wodika (part 2 - chapteres 7,11,12)

DNA

the molecule of heredity, passed from parents to offspring. stores biological information

chromosome

a single, large DNA molecule wrapped around proteins. located in the nuclei of eukaryotic cells. we have 23 pairs

XY

men

XX

women

what dna is made of

two strands of subunits (nucleotides) linked together in long chains

double helix

shape of DNA. spiral structure formed by two strands of DNA nucleotides held together by hydrogen bonds

dna replication

the natural process by which cells make an identical copy of a dna molecule, occurs when cells reproduce

complementary

fitting together, two strands of dna are said to be complementary. t and a. c ang g.

helicase

an enzyme that unwinds and unzips the dna double helix during dna replication

dna polymerase

an enzyme that reads the nucleotide sequence of a dna strand and incorporates complementary nucleotides into a new strand during replication. builds a new strang along each unzipped strand (helicase)

polymerase chain reaction (PCR)

laboratory technique to replicate a specific dna segment

James Watson and Francis Crick

solved the structure of dna

Rosalind Franklin

made xray diffraction pictures of dna

alleles

any of the alternative versions of the same gene that have different nucleotide sequences. created by mutations

diploid

having two copies of every chromosome

homologous chromosomes

a pair of chromosomes that both contain the same gene. one inherited from the mother, other from the father

phenotype

the visible or measurable features of an individual

genotype

the genetic makeup of an individual

gametes

specialized reproductive cells that carry one copy of each chromosome. sperm and eggs

haploid

having one copy of each chromosome. gametes for example

meiosis

a type of cell division that generate unique haploid gametes. happens in two events

zygote

a diploid cell that is able to develop into an adult organism. formed when a haploid egg is fertilized by a haploid sperm

mitosis

cell division that reproduces body cells

meiosis event 1 - recombination

maternal and paternal chromosomes pair and physically exchange dna segments

meiosis event 2 - independent assortment

alleles of different genes are distributed independently of one another during meiosis

heterozygous

having two different alleles for a given gene

homozygous

having identical alleles for a given gene

incomplete dominance

a form of inheritance in which heterozygotes have a phenotype that is intermediate between two homozygotes

codominance

a form of inheritance in which the effects of both alleles are displayed in the phenotype of a heterozygote

continuous variation

Variation in a population showing an unbroken range of phenotypes rather than discrete categories.

polygenic trait

a characteristic, such as height or skin color, that is influenced by two or more genes

multifactorial

An interaction between genes and the environment that contributes to a phenotype or trait.

epigenetics

Changes in gene expression that are not based on changes in the DNA sequence.