Unit 4: Genetics

Concept 1: DNA Structure and Replication

Vocabulary

• Nucleic Acid: macromolecule that holds genetic information

• Nucleotide: monomer of nucleic acid (made of sugar, phosphate, and nitrogen base)

• Chromosome: tightly coiled strands of DNA

• Gene: a section of DNA that has instructions to code for a protein

Objectives

1. DNA vs RNA

• DNA has:

  • a double helix structure

  • Adenine, Thymine, Guanine, and Cytosine

  • sugar = deoxyribose

    • Deoxyribonucleic acid

• RNA has:

  • a single strand structure

  • Adenine, Uracil, Guanine, and Cytosine

  • sugar = ribose

    • Ribonucleic acid

2. Base pairing rule

• Adenine ALWAYS pairs with Thymine in DNA

  • In RNA, Adenine pairs with Uracil

• Guanine ALWAYS pairs with Cytosine in DNA

3. Structure of a nucleotide

• Phosphate, sugar, and nitrogen base

  • Phosphate and sugar are connected by a strong covalent bond

  • Sugar and nitrogen base are connected by a strong covalent bond

  • The nitrogen bases from each side connect in the middle by a weak hydrogen bond

4. DNA replication

• A cell always needs to replicate it’s DNA before it divides

  • Steps:

    • 1. An enzyme unzips the DNA

    • 2. Free complementary bases in the nucleus match up with each side on the unzipped DNA

    • 3. Two identical DNA molecules are formed

5. DNA replication = semi conservative

• DNA is considered semi-conservative

  • the original strand is part of each new strand

  • half of the original DNA is in each of the new strands

Concept 2: Protein Synthesis

Vocabulary

• Protein synthesis: the process of reading the instructions in DNA to make a polypeptide

• Polypeptide: a chain of amino acids; can bind to others and fold into a protein

• Transcription: when DNA is copied into a complementary strand

• Genetic code: code of instructions for how to make proteins

• Codon: a set of three nucleotides on the mRNA

• Anticodon: “complementary” three nucleotides on the tRNA

• Amino Acid: monomer for making proteins, held together by peptide bonds

• Translation: the process of interpreting RNA into a protein

• Epigenetics: the study of changes in gene expression that are heritable

Objectives

1. The Central Dogma

• DNA —transcription—> mRNA —translation—> protein

• It needs to be a two step process

  • the info in DNA needs to get to the ribosomes

  • but DNA can’t leave the nucleus

  • so mRNA is used as a messenger

2. Roles of they 3 types of RNA

• There are 3 types of RNA

  • mRNA

    • the messenger that brings the genetic information from the nucleus to the ribosomes

  

  • tRNA

    • what transfers the amino acids to the ribosomes where the proteins are made

  

  • rRNA

    • the ribosomes where the proteins are made

3. Transcription

• Purpose: get the information on the DNA to the mRNA

• Occurs in: the nucleus

• Steps:

  • 1. DNA unzips

  • 2. Free nucleotides bind to one side of the DNA to form mRNA

  • 3. mRNA detaches from the DNA

  • 4. mRNA leaves the nucleus

  • 5. DNA zips back up

• Example:

  • DNA: TAC | ACC | GGA | GCG | TTT | ATT

  • mRNA: AUG | UGG | CCU | CGC | AAA | UAA

4. Translation

• Purpose: give the information from the mRNA to the tRNA to make a protein

• Occurs in: the ribosomes

• Steps:

  • 1. tRNA has anticodons that match with each codon

  • 2. each anticodon corresponds to a amino acid

  • 3. the tRNA reads the mRNA and drops off the correct amino acids in order to create a protein chain

• Example:

  • DNA: TAC | ACC | GGA | GCG | TTT | ATT

  • mRNA: AUG | UGG | CCU | CGC | AAA | UAA

  • tRNA: UAC | ACC | GGA | GCG | UUU | AUU

  • amino acids: met - try - pro - arg - lys - stop

5. Gene Regulation

• a highly regulated process

• turns genes ‘on’ and ‘off’

  • this is critical for cell differentiation

• Some genes are expressed, so they make the proteins they code for

• Some genes are turned ‘off’, they do not make the proteins they code for

• Regulatory proteins turn genes ‘on’ or ‘off’

• Example:

  • Eye color

  • You may have a blue eye gene and a brown eye gene, but only one of them will be regulated

  • So only one will show up- the one not turned ‘off’

6. Epigenetics vs Mutation

• Epigenetics- the study of changes in genes that are heritable

  • does not affect the DNA sequence

  • just a change in how the gene is expressed

Concept 3: Meiosis

Vocabulary

• diploid: cell with 2 full sets of chromosomes

• haploid: cell with 1 full set of chromosomes

• karyotype: a diagram that shows the number and visual appearance of the chromosomes in a cell

• meiosis:

• sexual reproduction:

• fertilization:

• homologous chromosomes:

• sister chromatids:

Objectives

1. Somatic Cells vs Gametes

• Somatic Cells are body cells

  • they have 2 full sets of chromosomes

• Gametes are sex cells

  • they have 1 full chromosome set

2. Autosomes vs Sex Chromosomes

• Autosomes

  • carry traits that make you who you are

• Sex Chromosomes

  • carry traits that determine your biological sex

3. Meiosis Happens Twice

• cells MUST go through meiosis division twice

  • gametes need to be haploid

  • WHY?

    • when an egg and sperm meet in fertilization, their DNA combines to make one offspring

    • so each egg and sperm needs to only have half the number of chromosomes so the offspring has the correct number

4. Purpose of Meiosis I vs Meiosis 2

• Meiosis 1: separate the homologous chromosomes

• Meiosis 2: separate the sister chromatids

5. Crossing Over

• crossing over is when genetic information swaps between homologous chromosomes

• this makes each daughter cell unique

6. Stages of Meiosis

• Meiosis I

  • Prophase I

    • homologous chromosomes pair up

  

  • Metaphase I

    • spindle fibers attach to the centromeres

  

  • Anaphase I

    • chromosomes are pulled apart

  

  • Telophase I

    • spindle fibers disappear

    • cell starts to split

• Meiosis II

  • Prophase II

    • spindle fibers appear and nuclear membranes break down

  

  • Metaphase II

    • spindle fibers attach to the centromeres

  

  • Anaphase II

    • spindle fibers pull the sister chromatids apart

  

  • Telophase II

    • nuclear membranes reform

    • cell starts to split in two

7. Meiosis vs Mitosis

• Mitosis

  • creates: 2 diploid, identical daughter cells

  • purpose: growth and repair

  • when does it happen: throughout life

  • type of reproduction: asexual

• Meiosis:

  • creates: 4 haploid, unique daughter cells

  • purpose: creating gametes

  • when does it happen:

    • males: throughout life

    • females: before birth

  • type of reproduction: sexual

8. Mistakes in Meiosis vs Mitosis

• Mitosis:

  • a mistake in mitosis creates a mutation that could cause the wrong proteins to me made

  • it leads to cancer sometimes

• Meiosis:

  • a mistake in meiosis creates a mutation that causes offspring to have too few or too many chromosomes

Unit 5: Heredity

Concept 1: Mendelian Genetics

Vocabulary

• genes: sections of DNA code for a protein

• alleles: different versions of the same gene

• homologous chromosomes: the matching chromosomes from our mom and dad

• homozygous: 2 of the SAME alleles

• heterozygous: 2 DIFFERENT alleles

• dominant: if present, the allele will always have that trait expressed

• recessive: the allele will only be expressed when the dominant allele is NOT present

• genotype: the actual alleles inherited

• phenotype: the physical traits

• Punnett square: a diagram that shows the probability of inheriting traits from parents with certain genes

• monohybrid cross: a cross between two organisms looking at one trait

• dihybrid cross: a cross between two organisms looking at two different traits

Objectives

1. Mendel’s experiments and laws

• Mendel crossed pea plants with different traits to see what their offspring would be like

  • from his research, he came up with 3 Laws of Inheritance

    • 1. Law of Dominance: dominant alleles always show over recessive alleles

    • 2. Law of Segregation: each gamete only receives one chromosome from each pair

    • 3. Law of Independent Assortment: the assortment of chromosomes for one trait doesn’t affect the assortment of chromosomes for another trait

2. Monohybrid crosses

• monohybrid cross: a cross between two organisms looking at one trait

• phenotypic ratio: the ratio of different phenotype possibilities

• genotypic ratio: the ratio of different genotype possibilities

• Example:

  • B = brown eyes

  • b = blue eyes

  • Anna has brown eyes, but only her mom had brown eyes. David has blue eyes. Find the phenotypic ratio and the genotypic ratio.

    • phenotypic ratio: ½ = brown, ½ = blue

      • 1 : 1

    • genotypic ratio: ½ = Bb, ½ = bb

      • 1 : 1

3. Dihybrid crosses

• dihybrid cross: a cross between two organisms looking at two different traits

• Example:

  • B = brown eyes

  • b = blue eyes

  • Anna has brown hair and brown eyes, but her dad was blonde and blue eyed. David has brown hair and brown eyes, but her mom was blonde and blue eyed.

    • phenotypic ratio: 9/16 = brown/brown, 3/16 = brown/blonde, 1/16 = blue/blonde, 3/16 = blue/brown

      • 9 : 3 : 3 : 1

    

Concept 2: Complex Inheritance Patterns

Vocabulary

• chromosome theory of inheritance: genes are located on chromosomes and the behavior of chromosomes during meiosis accounts for inheritance patterns

• epistasis: when one gene overshadows all the others and controls whether they are expressed

• carrier: someone how carries a recessive gene

Objectives

1. Incomplete dominance vs codominance

• incomplete dominance:

  • when both alleles are dominant

  • they mix when the genotype is heterozygous

  • Example:

    • A red flower and a white flower are crossed to make pink flowers

• codominance

  • when both alleles are dominant

  • they both show completely and separately

  • Example:

    • A white horse and an brown horse are crossed to make an appaloosa horse

2. Multiple alleles vs polygenic traits

• Multiple alleles

  • traits that are only on one gene

  • there are many different alleles of that trait

  • Example:

    • fur color in rabbits

• Polygenic traits

  • traits that are decided by multiple genes

  • Example:

    • eye color

3. Blood Type Example

• blood type has 4 different alleles, so it is an example of multiple alleles

• the A and B blood types form AB, so it is an example of codominance

4. Linked genes vs sex link traits

• Linked Genes

  • close together

  • more likely to be passed down together

• Sex linked traits

  • linked to one of the sex chromosomes

  • X-linked traits

    • women need both to get the trait (XX)

    • men only need one to get the trait (XY)

  • Y-linked traits

    • women never get them (XX)

    • men only need one to get the trait (XY)

5. Traits on sex chromosomes vs autosomes

Concept 3: Mutations and Pedigrees

Vocabulary

• mutation: any change in DNA

• mutagen: chemicals that can cause DNA mutations

• duplication: a mutation that changes the size of the chromosomes and results in multiple copiers of the same gene

• translocation: a mutation that causes pieces of non-homologous chromosomes to exchange segments

• nondisjunction: a mutation that happens when chromosomes don’t separate correctly during meiosis, resulting in 1 or 3 chromosomes in a group, rather than 2

• pedigree: a chart used to trace the phenotypes and genotypes in a family to determine whether people carry traits

Objectives

1. Somatic mutations vs germline mutations

• somatic mutations

  • occur in body cells

  • cause cancer

• germline mutations

  • occur in germ line cells (before meiosis)

  • cause mutated gametes

  • resulting in mutated offspring

2. Gene vs chromosomal mutation

• gene mutations

  • cause a change in the DNA sequence

  • occur during DNA replication

• chromosome mutations

  • occur during mitosis

  • cause a change in the number/location of the genes

3. Point mutations vs frameshift mutation

• point mutations

  • happen when one nucleotide is substituted for another

• frameshift mutations

  • happen when a nucleotide is deleted or added, causing everything after it to be wrong

4. Types of Inheritance Patterns

• 1. Autosomal Recessive

  • trait is a rare, recessive trait that often skips a generation

  • Example:

    • cystic fibrosis

  

• 2. Autosomal Dominant

  • trait is a very common, dominant trait that will never skip a generation

  • Example:

    • Huntington’s

• 3. Sex-linked recessive

  • trait is linked to the X chromosome

  • boys are more likely than girls to get it

  • it skips generations

  • Example:

    • color blindness

Concept 4: Genetic Engineering

Vocabulary

• biotechnology: refers to any technology used to the change genetic makeup of living things to make products

• genetic engineering: the direct manipulation of an organism’s genome using biotechnology

• recombinant DNA: artificially made DNA from 2 or more different sources

• genome: an organisms complete set of DNA; all its genes

• gene map: shows the location of genes on a chromosome

• polymerase chain reaction: a technique that allows you to copy a piece of DNA without a cell

• gel electrophoresis: a laboratory method that used an electrical current to separate DNA fragments based on their molecular size

• gene cloning: produces identical copies of a gene

• CRISPR: a gene editing technique that can delete, insert, or repair genes

• selective breeding: artificially breeding organisms with a desired trait

• pharming: producing pharmaceuticals in farm animals or plants

Objectives

1. Goal of genetic engineering

• The goals of genetic engineering are:

  • to alter an organism’s genome

  • to create products by doing this (antibiotics, vaccines, synthetic hormones, biofuels)

  • to ensure an organism and it’s offspring have a desired trait (creatin the ‘perfect’ organism)

2. Examples of genetic engineering

• Gene cloning:

  • produces identical copies of a gene (or genome)

• Gene therapy

  • CRISPR

    • a gene editing technique that can delete, insert, or repair

• Selective Breeding

  • artificially breeding organisms with a desired trait

  • how ‘pharm’ animals are mare

    • pharming: producing pharmaceuticals in farm animals or plants

Unit 6: Ecology

Concept 1: Intro to Ecology

Vocabulary

• Ecology: the study of relationship between organisms and between an organism and it’s environment

• Metabolism: all the chemical reactions of each cell in an organism that provide energy for life’s processes and create key molecules

• Organism: an individual member of a species or population

• Population: multiple organisms of the same species living together

• Community: multiple populations of different species living together

• Ecosystem: community plus all abiotic factors in the environment

• Biome: multiple ecosystems that share similar characteristics but are located in different areas

• Biosphere: the zone of life on Earth, encompassing all of Earth’s ecosystems

• Biodiversity: the variety of organisms considered at all levels

• Taxonomy: field of biology that classifies organisms, organizing them based on characteristics

• Binomial nomenclature: 2 name naming system that names organisms after their two most specific classification levels

• Dichotomous key: tool used for identifying organisms based on their characteristics

Objectives

1. Characteristics of life

1. Made of cells

2. Have a metabolism

3. Reproduce

4. Grow/develop

5. Respond to stimuli

6. Adapt and evolve

7. Contain DNA/RNA

2. Sexual vs asexual reproduction

• Sexual Reproduction:

  • two parents produce a genetically unique offspring

• Asexual Reproduction:

  • one parent produces a genetically identical offspring

3. Stimulus and Response

• Stimulus:

  • temperature increases

• Response

  • organism sweats and finds shade

4. Levels of ecological organization

1. Biosphere

2. Biome

3. Ecosystem

4. Community

5. Population

6. Organism

5. Levels of taxonomy

1. Domain

2. Kingdom

3. Phylum

4. Class

5. Order

6. Family

7. Genus

8. Species

Concept 2: Biogeochemical Cycles

Vocabulary

• Biogeochemical cycles: represent the movement of a particular form of matter through the living and non-living parts of an ecosystem

• Aquifer: the layer of permeable rock underground that can hold water

• Eutrophication: when a body of water becomes overly enriched in nutrients

Objectives

1. Matter must cycle

• Matter must cycle because there is a fixed amount of each element in the world, we can’t make more, so matter needs to cycle so all living things can use it how they need to

2. The water cycle

3. The carbon cycle

4. The nitrogen cycle

5. Impact of human and non-human organisms

• Water cycle:

  • Human: deforestation causes transpiration

  • Non-Human: plants transpirate water out of their leaves

• Carbon Cycle:

  • Human: Humans burn fossil fuels, releasing carbon into the atmosphere

  • Non-Human: animals eat plants, consuming carbon

• Nitrogen Cycle

  • Human: Humans fertilize plants, releasing too much nitrogen into the soil

  • Non-Human: plants take in nitrates and nitrites through their roots

Concept 3: Population Ecology

Vocabulary

• Population: a group of organisms of the same species living in the same place

• Population density: measures the number of individual organisms living in a defined space

• Survivorship curve: a graphic representation of mortality patterns

• Exponential growth: population grows without limits

• Logistic growth: population grown quickly at first, then levels off

• Carrying capacity: the max population a society can support

• Limiting factors: aspects of an environment that limit the size of a population

• Biotic: living

• Abiotic: non-living

• Density-dependent: have a bigger impact on more dense populations

• Density-independent: regulate population growth regardless of size and density

Objectives

1. High population density vs low population density

• High Density:

  • causes: abundant resources, immigration, high birth rate, low death rate

• Low Density:

  • causes: few resources, emigration, low birth rate, high death rate

2. Logistic vs exponential population growth

• Logistic Growth:

  • can only support so much; population will stop growing after a point

• Exponential:

  • doesn’t stop growing; no limit

3. Survivorship curves

1. Type I: late loss, few offspring, heavy parental care (ex: humans)

2. Type II: constant loss, unaffected by age (ex: birds)

3. Type III: early loss, many offspring, low parental care (ex: reptiles)

4. Types of dispersion patterns

5. Limiting factors

Concept 4: Human Impact

Vocabulary

• Sustainability: a balance between Earth’s resources, human needs, and the needs of other species

• Ecological (carbon) footprint: the amount of carbon emitted and its environmental impact

• Greenhouse effect: the normal warming effect when gases trap heat in the atmosphere

• Invasive species: non-native species introduced to an ecosystem that negatively harms

Objectives

1. Human impact of biogeochemical cycles

• Water cycle:

  • deforestation decreases transpiration

• Carbon cycle:

  • we burn fossil fuels, releasing CO2

• Nitrogen cycle:

  • fertilizers release too much nitrogen into the soil

2. Renewable and non-renewable resources

• Renewable: replenished faster than used

  • geothermal, wind, water, solar

• Nonrenewable: used faster than replenished

  • coal, oil, natural gas

3. Technology

• Agricultural Technology

  • goal: increase food productivity

  • pro: high crop productivity

  • con: reduces soil fertility

• Alternative Energy Technology

  • goal: provide clean energy to society

  • pro: environmentally friendly

  • con: many geographic limitations

• Industrial Technology

  • goal: increase manufacturing efficiency

  • pro: creates better quality products

  • con: displaces many jobs

4. Global Warming

• Human contribution to global warming:

  • burn fossil fuels, releasing CO2 causing the Greenhouse effect to increase

  • CFC’s deplete the ozone layer, letting the sun’s UV rays tog et to Earth

5. Human impact of biodiversity

• Polluting the earth with garbage

• destroying animal’s habitats (deforestation, etc.)

• introducing invasive species to new ecosystems

Concept 5: Succession

Vocabulary

• Ecological succession: the process of ecological change in an ecosystem where one community is replaced by another over time

• Primary succession: formation of a brand new ecosystem

• Secondary succession: recovery of an old ecosystem

• Pioneer species: the first organisms to grow in a new environment and help create soil

• Climax community: a mature and stable community of plants and animals

• Stable ecosystem: one that remains relatively constant, with predictable changes

Objectives

1. Primary vs Secondary Succession

• Primary Succession:

  • causes: volcano, melting glacier

  • starts: with bare rock

• Secondary Succession:

  • causes: fire, flood, hurricane

  • starts: with dirt

2. Human impact on ecological succession

• humans are the cause of a lot of secondary succession. We clear land to use for farming, we deforest areas, and we cause a lot of forest fires

3. Pioneer species

• Primary pioneer species

  • lichen is the pioneer species so it can form dirt for other organisms to grow

• Secondary pioneer species

  • small shrubs and weeds grow first because there is already dirt there

Concept 6: Relationships

Vocabulary

• Habitat: the actual area in an ecosystem where an organisms lives, including all its abiotic and biotic resources

• Niche: all the things an organism needs and does within its habitat (it’s role)

• Predator: the one that kills for food

• Prey: the one that is killed as food

• Keystone species: a species critical for the survival of others

• Competitive exclusion principle: no two species can occupy the same niche for an extended period of time

• Symbiosis: any interaction that involves a close, physical relationship between two species

Objectives

1. Predator/Prey relationship

• the predators keep the prey form growing too much in numbers, then when there are less prey, the number of predators will also go down, so they balance each other out

2. Predation vs parasitism

• Predators:

  • kill other animals so they can eat them

• Parasites:

  • try to keep their host organism alive so they can use their nutrients

3. Interspecific vs Intraspecific competition

• Interspecific: a lion and cheetah fighting for food

• Intraspecific: lion fighting a lion for food

4. Symbiotic relationships