DNA, Cell Cycle, Mitosis, Protein Synthesis, Biotechnology, Meiosis, Genetics, Evolution, Diversity of Life

DNA, Cell Cycle, Mitosis

• Nucleotide: Circle an individual nucleotide on a DNA diagram.
• DNA Bonds: Label the types of bonds in different parts of the DNA molecule (covalent and hydrogen bonds).
• DNA Components: Identify where you would find sugars, phosphates, and nitrogenous bases on a DNA diagram.
• Nucleotide Diagram: Draw a diagram of a nucleotide, labeling all three key parts (sugar, phosphate, nitrogenous base).
• DNA Replication:
  • Initiation: DNA is unzipped, and proteins bind to the DNA.
  • Elongation: Polymerase adds nucleotides to the DNA strand.
  • Termination: Enzymes remove and repair any mistakes, resulting in two new DNA helices.
• DNA vs. RNA:
  • Similarities: A, G, C nucleotides, covalent bonds in the sugar-phosphate backbone.
  • Differences: DNA contains T nucleotide, RNA contains U nucleotide; DNA is double-stranded (held by hydrogen bonds), RNA is single-stranded.
• Why Cells Reproduce:
  1. Surface area to volume ratio gets too big, limiting transport of materials.
  2. To replace damaged or dead cells.
  3. Reproduction is a characteristic of life.

Interphase

• G1 Phase (Growth): First stage after cell division; cell grows in size.
• S Phase (Synthesis): DNA is copied.
• G2 Phase (More Growth): Cell prepares for mitosis/meiosis.

Mitosis

• Description of mitosis steps alongside with figures (figures were not provided and cannot be generated).
• Chromosomes Align: Chromosomes line up in the middle of the cell. The centromere is connected by a spindle fiber to a centriole.
• Sister Chromatids Separate: Spindle fibers shorten to pull the sister chromatids apart. Individual chromosomes move to opposite sides of the cell.
• Cell Division: The cytoplasm pinches in half, and two new identical daughter cells are formed.
• Chromosome Condensation: Chromosomes become visible. Spindle fibers form as the centrioles move to the ends of the nucleus. The nuclear envelope starts to break down.
• New Nuclei Form: Chromosomes unwind, and two new nuclear envelopes form.
• Cell Cycle Regulation:
  • Regulators (cyclins) ensure everything is correct before moving on to the next phase.
  • Without regulation, mistakes can occur, potentially leading to cancer.

Protein Synthesis + Biotechnology

• From DNA to Protein: DNA contains the instructions that polymerase transcribes into RNA. RNA acts as a messenger, leaving the nucleus and going to the ribosome. The ribosome matches amino acids to the RNA codons to make a protein.
• Protein Synthesis Diagram:
  1. Cell membrane
  2. Cytoplasm
  3. DNA
  4. Nucleus
  5. Transcription
  6. mRNA
  7. Translation starting (follow arrows)
  8. tRNA
  9. Amino acid chain = protein
  10. Ribosome
• Original DNA Sequence:
  • Original DNA sequence: ATG GTA CTC ATA CCT TGA ATC
  • Antiparallel DNA: TAC CAT GAG TAT GGA ACT TAG
  • mRNA: AUG GUA CUC AUA CCU UGA AUC
  • Amino acids: Met Val Leu Ile Pro Stop
• Mutated DNA Sequence:
  • Mutated DNA sequence: ATG GTA TCA TAC CTT GAA TC
  • Antiparallel strand: TAC CAT AGT ATG GAA CTT AG
  • mRNA: AUG GUA UCA UAC CUU GAA UC
  • Amino acids: Met Val Ser Tyr Leu Glu
• Mutation Type: Frameshift mutation where an amino acid was deleted, affecting every amino acid after the change.
• DNA Fingerprinting: Son 2 (S2) is not biologically related to the parents because his bands do not match up to either parent.
• Transgenic Bacteria for Human Insulin: Cut the human insulin gene out of the human chromosome using restriction enzymes, cut open the bacterial plasmid with the same restriction enzyme, insert the DNA into the plasmid using DNA ligase (recombinant DNA), add it to bacteria, which will take up the plasmid and start making human insulin protein (GMO).
• GMOs (Genetically Modified Organisms): Bacteria making insulin, Golden Rice, spider silk-producing goats, etc.

Meiosis + Genetics

• Type of Reproduction for Skin Cell Replacement: Asexual reproduction (mitosis) is used because it produces exact copies of the original cell. It will also be a diploid cell.
• Steps in Meiosis That Introduce Genetic Variation:
  1. Crossing over between homologous chromosomes in prophase I.
  2. Independent assortment of chromosomes.
  3. Random fertilization.
• Haploid vs. Diploid:
  • Diploid cells have two copies of every chromosome and are the normal state of zygotes.
  • Gametes are haploid and have one copy of each chromosome.
• Chromosome Count:
  • If a diploid cell has 8 homologous pairs of chromosomes, there are 16 total chromosomes (8 \times 2 = 16).
  • After meiosis, each daughter cell will have 8 chromosomes (8 \times 1 = 8) because they are now haploid.
• Mitosis vs. Meiosis Outcomes:
  • Mitosis results in cells with the same number of chromosomes as the original cell.
  • Meiosis results in cells with half as many chromosomes (haploid).
• Meiosis Steps:
  • In prophase I, chromosomes form tetrads or pairs of homologous chromosomes.
  • In metaphase I, they line up two by two instead of single file.
  • In anaphase I, whole chromosomes move to each side of the cell instead of halves.
  • The second round of meiosis proceeds similar to mitosis.
• Alleles and Phenotypes: Differences in DNA lead to different RNA, which leads to different proteins, resulting in different phenotypes or traits.
• Dominant Phenotype, Recessive Child: Yes, if both parents are heterozygous (Aa), they have a 25% chance of having a child with a recessive phenotype.
• Genotype "Aa": Two alleles, one dominant (A) and one recessive (a).
• Elephant Ear Shapes:
  • Male genotype: aa (rounded ears)
  • Male phenotype: rounded ears
  • Female genotype: Aa (squared ears)
  • Female phenotype: squared ears
  • Offspring probability: 50% chance of rounded ears.
• Black and White Dog Puppies: Codominance, where both phenotypes are shown at the same time (puppies are black and white).
• Flower Color Crossing: Incomplete dominance, where traits mix (dark blue and white flowers result in light blue flowers).
  BB = dark blue, B^IB^I = white, BB^I = light blue
• Blood Type Inheritance: A heterozygous B blood type man (IBi) marries a woman with O blood (ii). There is a 50% chance they will have a child with O blood.
• Colorblindness: A man who is not colorblind (X^RY) and a woman who is a carrier (X^RX^r) have:
  • 25% chance of having a colorblind baby.
  • 50% chance of having a colorblind boy.
• Down Syndrome: A chromosomal disorder caused by nondisjunction, where chromosomes don’t separate correctly in anaphase, resulting in three copies of chromosome 21.
• Samwise Gamgee and Rosie: Rosie’s genotype is Aabb (blond, curly hair). Sam must be aa for blond hair so his genotype must be Aabb.
• Dragon Genetics: Red, acid-spitting dragon (Aabb) mates with a black, heterozygous fire-breathing dragon (aaBb). Probability of baby being black and spitting acid (aabb) is 1/4.
• Smith Family Pedigree:
  • The disease is autosomal recessive.
  • Harry’s genotype: Aa (normal phenotype)
  • George’s genotype: AA (normal phenotype)
  • Martha’s genotype: Aa (normal phenotype)

Evolution

• Natural vs. Artificial Selection: Both select for desirable characteristics and are examples of evolution. In artificial selection, humans choose what is desirable. In natural selection, the environment chooses what is favorable.
• Macroevolution vs. Microevolution: Macroevolution: fossil record. Microevolution: finches in the Galapagos Islands evolving different beaks or coloring.
• Principles of Natural Selection:
  1. Variation: populations have lots of different combinations of alleles leading to lots of variation between individuals.
  2. Overproduction: populations reproduce until resources get limited, leading to intense competition.
  3. Selection: some individuals are better suited to their environment and better at getting resources they need, so will survive longer than the others.
  4. Differential reproduction: individuals that are best fit survive longer and produce more offspring, passing on their beneficial traits. Eventually, the entire population shifts to the new phenotype.
• Causes of Evolution:
  1. Natural selection
  2. Mutation
  3. Genetic drift (affects small populations the most)
• Geographic Isolation and Speciation: A population gets separated from each other physically and now live in different environments. Environmental pressures cause them to build up changes over time. They eventually become reproductively isolated, becoming two different species.

Viruses and Treatment

• Ear Infection Treatment: A bacterial infection should be treated with an antibiotic. Antibiotics treat current bacterial infections, vaccines prevent future viral infections.
• Lytic Infection Steps:
  1. Infect: Virus injects its DNA and hijacks host cell.
  2. Proteins: Cell follows virus DNA to produce new virus proteins.
  3. Assemble: Cell puts virus parts together.
  4. Repeat: Virus is released to infect more cells.
• Viruses and Characteristics of Life: Viruses use energy and interact with cells but are not made of cells. Therefore, they are not considered alive.
• Diversity of life: Look back over notes to be able to identify organs and match them to their functions. Only responsible for the ones listed at the front of this study guide.