Biology Semester 2

DNA is has ___ strands

2

What does each nucleotide contain?

a phosphate group, a deoxyribose sugar, and a nitrogenous base.

What are the four nitrogenous bases of DNA

Adenine, Thymine, Cytosine, and Guanine

What are the base pair rules for DNA

Adenine pairs with Thymine and Cystosine pairs with Guanine

What type of bond holds the bases together

Hydrogen Bonds

What type of bond holds the sugar-phosphate backbone together?

Covalent bonds

What does DNA store?

Genetic Information

Prokaryotes vs. Eukaryotes: Nucleus

Prokaryote: No nucleus, Eukaryote: Nucleus

Prokaryotes vs. Eukaryotes: Organelles

Prokaryote: No membrane-bound organelles, Eukaryotes: Membrane-bound organelles

Prokaryotes vs. Eukaryotes: Size

Prokaryotes are smaller than Eukaryotes

Prokaryotes vs. Eukaryotes: Complexity

Prokaryotes are simpler than the more complex eukaryotes

Prokaryotes vs. Eukaryotes: DNA

Prokaryote: Circular, Eukaryote: Linear

Prokaryotes vs. Eukaryotes: Examples

Prokaryotes: Bacteria, Eukaryotes: Plants and animals

Genome

all genetic material in an organism

Gene

section of DNA that codes for a trait/protein

Chromosome

tightly coiled DNA containing many genes

Homologous Chromosomes

chromosome pairs with the same genes (one from each parent)

Relationship between genes, chromosomes, and genome

Genes are found on chromosomes, and all chromosomes together make up the genome

DNA vs. RNA: Sugar

DNA: Deoxyribose, RNA: Ribose

DNA vs. RNA: Strands

DNA: Double, RNA: Single

DNA vs. RNA: Bases

DNA: A, T, C, G RNA: A, U, C, G

DNA vs. RNA: Purpose

DNA: Stores genetic information, RNA: Helps male proteins

DNA vs. RNA: Location

DNA: Nucleus, RNA: Nucleus and Cytoplasm

What does RNA use instead of Thymine

Uracil

Central Dogma

explains how genetic information flows, DNA to RNA to Protein

Transcription

DNA is copied to mRNA, happens in the nucleus

Translation

mRNA is read by ribosomes, protein is built from amino acids, happens at ribosomes in cytoplasm

Purpose of Transcription and Translation

creates proteins needed for cell function

What come first, Transcription or Translation

Transcription

mRNA function

Carries code for DNA

tRNA

Brings amino acids

rRNA

Makes up ribosomes

Codon

3-base sequence on mRNA

Anticodon

matching sequence on tRNA

To go from a DNA strand to codons

translate DNA to mRNA and then those are the codons that then code for amino acids

What are the three types of point mutation

Substitution, Insertion, and Deletion

Substitution

One base is replaced, only changes one codon

Insertion

One base is added, effects all codons after

Deletion

One base removed, effects all codons after

Silent Mutation

No amino acid change

Nonsense mutation

stop codon formed

Frameshift

reading frame changes

Missense mutation

different amino acid

Steps of replication

1. DNA unzips

2. Complementary bases are added

3. Two identical DNA molecules form

Semi-conservative replication

Each new DNA molecule contains 1 original strand and one new strand

Phases of Mitosis

1. Prophase

2. Metaphase

3. Anaphase

4. Telophase

5. Cytokinesis

Cell Cycle Phases

1. G1

2. S

3. G2

4. Mitosis

5. Cytokinesis

What happens in the G1 phase

the cell grows

What happens in the S phase

DNA is replicated

What happens in the G2 phase

the Cell prepares for division

What happens in the Mitosis phase of the cell cycle

Nucleus divides

What happens in cytokinesis

the cytoplasm divides, and the one cell becomes two

What happens during prophase

Chromosomes condense

What happens during metaphase

chromosomes line up in the center

What happens during anaphase

Sister chromatids separate

What happens during telophase

new nuclei form

Cancer

is uncontrolled cell division

Causes of cancer

• mutations in genes controlling cell cycle

• failure of checkpoints

• damaged cells continue dividing

Mitosis vs. Meiosis: number of cells produced

Mitosis: 2, Meiosis: 4

Mitosis vs. Meiosis: Chromosome number

Mitosis: Diploid, Meiosis: Haploid

Mitosis vs. Meiosis: Cell Type

Mitosis: Body Cells, Meiosis: Gametes

Mitosis vs. Meiosis: Genetic Makeup

Mitosis: Identical, Meiosis: Variable

Mitosis vs. Meiosis: Purpose

Mitosis: Growth/repair, Meiosis: Reproduction

Diploid

two chromosome sets

Haploid

one chromosome set

Phases of Meiosis

• Prophase I

• Metaphase I

• Anaphase I

• Telophase I

• Interkinesis

• Prophase II

• Metaphase II

• Anaphase II

• Telophase II

What occurs in Prophase I

crossing over

What occurs in Metaphase I

homologous pairs line up

what occurs in anaphase I

homologous chromosomes separate

What is interkinesis

a short resting period between divisions

Monohybrid

One trait cross

Dihybrid

Two trait cross over

Dominant vs. Recessive

Dominant allele masks recessive allele, recessive trait appears only with two recessive alleles

Incomplete Dominance

Blended trait

Codominance

Both traits expressed but not blended

Polygenic

Many genes affect one trait

Gene

DNA segment

Allele

version of a gene

Genome

all DNA

Genotype

Genetic makeup

Phenotype

physical trait

AA

Homozygous Dominant

Aa

Heterozygous

aa

Homozygous Recessive

Nondisjunction

chromosomes fail to separate properly

X-linked recessive

Gene carried on X chromosome

Evidence for Evolution

Anatomy, Fossils, Molecular, Artificial Selection, Biogeography, Embryology, Natural Studies

Evolution

change in allele frequencies in a population over time

Natural Selection

best adapted to survive/reproduce

Gene flow

Movement of genes between populations

Mutation

DNA changes

Sexual Selection

Traits improve mating success

Genetic Drift

Random Changes in small populations

Species

organisms that can reproduce and produce fertile offspring

Speciation

occurs when populations become reproductively isolated

Rat Heart Function

Pumps blood

rat lungs function

gas exchange

rats liver function

detoxifies chemicals with bile

rats small intestine function

nutrient absorption

Rats large intestine function

water absorption