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Erwin Chargaff (1950)

determined DNA is species specific and the "Chargaff's Rules" which are base pairings

Rosalind Franklin and Maurice Wilkins (1952)

used photographs of DNA fibers to determine dimensions of the strands and that phosphates were on the outside

James Watson and Francis Crick (1953)

Built the first model of DNA as a double helix structure

What does DNA stand for?

Deoxyribonucleic Acid

Where is DNA primarily located in a cell?

In the nucleus

What is the structure of DNA?

double helix shape, two stranded, and antiparallel strands

What are the four nitrogenous bases in DNA?

Adenine (A), Thymine (T), Cytosine (C), Guanine (G)

What is the primary function of DNA?

Stores genetic information used to make proteins

What is RNA also known as?

Ribonucleic Acid

What are the three types of RNA?

mRNA, tRNA, and rRNA

Is RNA single-stranded or double-stranded?

Single-stranded

What are the nitrogenous bases found in RNA?

Adenine (A), Uracil (U), Cytosine (C), Guanine (G)

What role does RNA play in relation to DNA?

Helps the DNA make proteins

Base Pairing for DNA

Thymine-adenine

Cytosine- guanine

Base Pairing for RNA

Adenine-uracil

Cytosine-guanine

Gene

A segment of DNA on a chromosome that codes for a specific trait

semiconservative

Each DNA molecule consists of one original strand and one new strand

transcription

Produces mRNA from DNA, in nucleus, DNA unwinds the gene and the RNA polymerase uses DNA as a template to make a mRNA copy that leaves the nucleus

translocation

mRNA binds to a ribosome, the codons get read by the tRNA, the tRNA brings in the right amino acid that matches the codon, the amino acids link together to form protein

central dogma

DNA -> RNA -> Protein

Codon

a sequence of 3 nucleotides that code for an amino acid

Okazaki fragments

The fragments that aren't continuous and are in segments after the primase adds primer

Antiparallel

refers to the directionality with DNA strands, one going up and the other down

Back bones of DNA strands

the free phosphate group and the free OH group on the sugar

DNA Replication

the process of making a copy of DNA

5' end

the free phosphate group

3' end

The free OH group on the sugar

topoisomerase

An enzyme that prevents super coils and allows for just the right coils, stops from over twisting

primase

An enzyme that synthesizes short RNA primers which are the starters (on the 3'), helps the polymerase to know where to start

helicase

An enzyme that separates the DNA strands

ligase

An enzyme that links the new pieces of DNA together

DNA Polymerase

An enzyme that adds the nucleotides and proof reads the new strand of DNA

RNA polymerase

in transcription it uses DNA as a template to make a mRNA copy

2 steps of protein synthesis

transcription and translation

Which is always the start codon?

AUG

mRNA

carries DNA message as codons

tRNA

matches the anticodon to the mRNA codon and brings in the correct amino acids

rRNA

makes up ribosomes

Anticodon

group of three bases on a tRNA molecule that are complementary to an mRNA codon

chromosomes

condensed DNA molecule with part or all of the genetic material of an organism (humans have 23 pairs)

somatic cells

body cells that aren't passed on to offspring, goes through mitosis

Ex: muscle cells

gametes

sex cells, eggs (female), sperm (male), gets passed on to offspring, goes through meiosis

autosomes

Any chromosome that is not a sex chromosome

sex chromosomes

Chromosomes that determine the sex of an individual, XX (female), XY (male)

homologous chromsomes

two chromosomes with the same genes but have different versions of the allele

diploid

two copies of each chromosome, include somatic cells, 2n

haploid

1 copy of each chromosome, includes gametes, don't have homologous chromosomes, n

fertilization

uniting of a sperm (n) and an egg (n), n+n=2n, results in a diploid zygote which is a fertilized egg

zygote

fertilized egg

mitosis

starts with one diploid (2n) and ends with two diploid

meiosis

starts with one diploid and ends with 4 haploids, somatic cells -> sex cells (gametes)

How many cell divisions occur in meiosis?

Meiosis has 2 cell divisions.

How many daughter cells are formed in mitosis?

Mitosis forms two daughter cells.

How many new cells are created in meiosis and what is their chromosome number?

Meiosis forms 4 new cells with half of the original number of chromosomes.

What type of reproduction is mitosis associated with?

Mitosis is associated with asexual reproduction.

What type of reproduction is meiosis associated with?

Meiosis is associated with sexual reproduction.

What type of cells does meiosis produce?

Meiosis results in haploid cells.

What type of cells does mitosis produce?

Mitosis results in diploid cells.

What are the purposes of mitosis?

Mitosis is for repairs, growth, and asexual reproduction.

What is the purpose of meiosis?

Meiosis is to create sex cells needed for sexual reproduction.

Meiosis 1

separates the homologous chromosomal pairs, ends with two cells that have a unique combination of 23 duplicated chromosomes from both parents

Meiosis 11

separates the sister chromatids, ends with 4 haploid cells with a combination of chromosomes from both parents

crossing over (meiosis 1 prophase)

when homologous chromosomes pairs come together in prophase 1 and the chromatids become twisted around each other, creates new combinations of alleles

independent assortment (meiosis 1 anaphase and telophase)

homologous pairs line up opposite of each other randomly, then these pairs are separated and so one of each chromosome gets put in a daughter cell, created lot of of possible combinations of the chromosomes