Chapter 2 Flashcards by Pedrin C

Natural selection

the most critical mechanism for evolutionary change; described by charles darwin

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fixity of species

the notion that species, once created, can never change

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cell

smallest unit that can be considered to be alive

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DNA

Deoxyribonucleic acid

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Somatic cells

make up structures of body

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gametes

sex cells that make spermatoza and ova

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Zygote

The single cell that is formed when an egg and sperm cell unite

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What are Chromosomes

humans have 46 chromosomes
arranged in 23 pairs
22 autosome and one pair of sex chromosomes x and y

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Define chromosome

bodies found in the nucleus that contains genetic material

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Chromatid

Strands of replicated chromosome

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karyotype

classification and arrangement of photographed chromosomes

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Locus

physical location on a chromosome where a gene is found

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Homologous Chromosomes

chromosomes with corresponding loci. They share the same genes but no necessarily the same alleles.

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Mitosis

Normal cell division. Most form of cell division

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Meiosis

the form of cell division that produces gametes

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Evolution

a change of gene frequency OF A POPULATION over time

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Gene

A sequence of DNA that codes for a specific product (protein)

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nucleotide

building blocks of DNA molecule

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Two major functions of DNA

Replication and Protein synthesis

Codon

biochemistry a sequence of three nucleotides which together form a unit of genetic code in a DNA or messenger RNA molecule

Anticodon

A sequence of three nucleotides on a strand of transfer RNA that can form base pairs with a specific trinucleotide sequence on a strand of messenger RNA during translation

Mutation

Alterations in the genetic material

two kinds of mutations

Chromosomal and point

Chromosomal Mutations

change in number
change in structure 
-deletion
-duplication
-inversion
-translocation

point mutation

deletions additions substitutions

natural selection

Mechanism of evolutionary change

Fixity of species

Notion that species, once created, can never change. Fijesas de las especias

reproductively isolated

pertaining to groups of organisms that mainly because of genetic differences are prevented from mating and producing offspring with members of other groups

binomial nomenclature

in taxonomy whereby genus and species names are used to refer to species

Taxonomy

the branch in science that uses rules of classifying organisms on the basis of evolutionary relationships

Catastrophism

view that earths geological landscape is the result of violent cataclysmic events

uniformitarianism

theory that the earths features are the result of longterm processes that continue to operate in the present as they did in the past

fitness

pertaining to natural selection, a measure of reproductive success of individuals

reproductive success

the number of reproductive offspring an individual produces and rears to reproductive age. an individuals genetic contribution to the next generation

selective pressures

forces in the environment that influences reproductive success in individuals

genome

the entire genetic makeup of an individual or species

biological continuity

when expressions of a phenomenon continuously grade into one another so that there are no discrete categories, they exist on a continuum

somatic cells divide by

mitosis

gamete cells divide by

meiosis

two major functions of a DNA

replication and Protein Synthesis

nucleotides made of 3 basis

phosphate sugar and a base (Adenine Thymine Cytosine Guanine ATCG)

what are the back bone to a nucleotide

phosphate and sugar

spiral shape

double helix

explain DNA replication

Enzymes comes and breaks hydrogen bond bases are now open free flowing nucleotides connect to proper base available forms a new strand and using phosphate and sugar connect it all together

Explain protein Synthesis

transcription - Enzyme separates a part of a DNA - sends free flowing RNA and they connect to open available basis - new mRNA is made and sent out of nucleus to ribosome Translation - ribosome is like a factory and sole purpose is to make protein. - body sends tRNA to ribosome - body sends mRNA to robosome - ribosome connects tRNA with open basis on mRNA. - New protein DNA is made