1DNA (name)
deoxyribonucleic acid
2DNA
molecule that stores genetic information in all organisms
3Nitrogen-rich bases
Adenine, Thymine, Guanine, Cytosine
4Deoxyribose sugar
the sugar portion of a deoxyribose nucleotide
5Adenine pairs with
Thymine
6Guanine pairs with
Cytosine
7Phosphate
connects to sugars
8DNA structure
double helix
9Chromosomes
packages of DNA
10Genes
sections of DNA that contain information
13Somatic cells have __ chromosomes
46 (23 pairs)
14Gametes have __ chromosomes
23 (no pairs)
15Mitosis
reproduction of somatic cells
16Meiosis
reproduction of gametes
17Homologous pairs
A pair of chromosomes of the same type, one from each parent.
18Process of copying DNA
replication
19Diploid cells
cells that have pairs of chromosomes
20Haploid cells
A cell containing only one set of chromosomes
21Stages of mitosis
prophase, metaphase, anaphase, telophase
22DNA is made of
nucleotides
23Heritable traits
traits that are passed genetically from parent to offspring
24natural selection
A natural process resulting in the evolution of organisms best adapted to the environment
25genetic variation
Heritable variations in a population
26evolution
the apparent change in heritable traits in a species over time
27species
a population that can breed and produce fertile offspring
28phenotype
observable characteristics
29genotype
genetic makeup of an organism
30Evolution by natural selection requires
traits are inherited, offspring vary in heritable traits, competition for survival
31Selection pressures (examples)
predation, competition, disease, temperature, soil nutrients, natural disasters, water
32Selection pressures (definition)
natural forces that promote the reproductive success of some individuals more than others
33speciation
Formation of new species
34steps of speciation
variation, isolation, selection
35interphase
period of the cell cycle between cell divisions in which the cell grows and copies DNA
36prophase
DNA condenses into visible double stranded chromosomes
37metaphase
chromosomes line up in the middle of the cell
38anaphase
chromosomes separate and move to opposite ends of the cell
39telophase
two identical nuclei form
40Cytokinesis
division of the cytoplasm to form two separate daughter cells
41cell plate
forms across the center of a plant cell near the end of telophase
42centromere
structure that connects the two sister chromatids
43Centrioles
Cell organelle that aids in cell division in animal cells only
44chromatid
one half of a duplicated chromosome
45alleles
variations of genes
46the trait the allele codes for could either be
dominant or recessive
47homozygous
has two identical alleles for a trait
48heterozygous
has two different alleles for a trait
49dominant allele
an allele whose trait always shows up in the organism when the allele is present
50recessive allele
an allele that is hidden whenever the dominant allele is present
51trait
specific characteristic of an individual
52causes of genetic variation
mutation, recombination, gene flow
53mutation
alteration in DNA sequence
54recombination
pieces of DNA are broken and recombined to produce new combinations of alleles
55reproduction (genetic variation)
forms new combinations of genes
56gene flow
exchange of genes between populations
57natural selection is a _______ of evolution
mechanism
58evidence for evolution
fossils, comparative anatomy, embryology, DNA, species distribution
59how does reproductive isolation lead to speciation?
two separate populations of organisms are no longer able to exchange genes
60spindle fibres
proteins that pull the chromosomes towards the poles
61dna replication stages
opening of double helix, separation of strands, assembly of new dna segment