Notes _ Knowt

Page 1: Meiosis and Genetics

1. Meiosis

  • Know the cell cycle

    • Stages: G1, S, G2, M (Mitosis)/Meiosis

  • When DNA is replicated

    • During the S phase of the cell cycle

  • How gametes form

    • Through meiosis, which reduces the chromosome number by half, resulting in haploid gametes

  • Role of Independent assortment

    • Homologous chromosomes are randomly distributed to gametes during meiosis I, leading to genetic variation

  • How to determine the number of unique gametes

    • Use the formula 2^n, where n = the number of homologous pairs

  • Vocabulary:

    • Chromosome: A structure containing DNA and protein found in cells

    • Homologous chromosome: A pair of chromosomes from each parent that are similar in shape, size, and genetic content

    • Chromatin: The relaxed form of DNA in the nucleus, not tightly coiled

    • Sister chromatid: Two identical copies of a chromosome formed during DNA replication

  • Disorders due to non-disjunction

    • Down syndrome, Turner syndrome, Klinefelter syndrome, Triple X syndrome, Patau syndrome, Edward syndrome, Trisomy 21

2. Genetics

  • Who is Gregor Mendel

    • The father of genetics; known for his work on inheritance patterns in pea plants

  • How to do a mono and dihybrid cross

    • Monohybrid cross: A genetic cross involving one trait; use a Punnett square to predict offspring genotypes/phenotypes

    • Dihybrid cross: A genetic cross involving two traits, using a 4x4 Punnett square

  • Vocabulary:

    • Allele: Different forms of a gene

    • Homozygous: Having two identical alleles for a trait

    • Heterozygous: Having two different alleles for a trait

    • Recessive: An allele that is masked by a dominant allele

    • Dominant: An allele that expresses its trait when present

    • Sperm and egg gametes: Male and female sex cells, respectively

    • Zygote: The fertilized egg that develops into an embryo

    • Diploid/Haploid: Diploid (2n) contains two complete sets of chromosomes, haploid (n) contains one set

    • True-breeding vs Hybrids: True-breeding organisms have identical alleles, hybrids have different alleles

    • Genotype vs Phenotype: Genotype is genetic makeup, phenotype is physical expression

    • Mutation: A change in the DNA sequence

  • Sex determination

    • In humans, females are XX and males are XY

  • Monohybrid and Dihybrid Crosses

    • Analyze expected ratios using Punnett squares

  • How to calculate expected phenotypic and genotypic ratios

    • Use ratios derived from Punnett squares

  • Genetics of simple inheritance

    • Simple dominant: occurs when an inherited trait is coded for by a single gene and that gene has two versions, or alleles: the dominant version and the recessive version

    • recessive dominant: only expressed when two copies of the allele are present

    • Expected phenotypic ratios in monohybrid crosses: 3:1 ratio of dominant to recessive traits

    • Expected phenotypic ratios in dihybrid crosses: 9:3:3:1 ratio

  • Exceptions to simple inheritance:

    • Sex-linked: characteristics (or traits) that are influenced by genes carried on the sex chromosomes

    • Polyallelic traits: traits determines by multiple alleles or more than two

    • Codominant traits: an inheritance pattern where two alleles are expressed equally, and neither allele is dominant or recessive

    • Polygenic traits: a physical characteristic influenced by multiple genes

    • Incomplete dominant traits: Wavy hair: When someone inherits one allele for curly hair and one for straight hair, they will have wavy hair

      Ex: Wavy hair: When someone inherits one allele for curly hair and one for straight hair, they will have wavy hair

Page 2: Central Dogma and Inheritance

1. Central Dogma

  • DNA Replication

    • Base compliments: A-T, C-G for DNA

    • Parts of a nucleotide: phosphate group, sugar, and nitrogenous base

    • 3 enzymes involved: DNA helicase (unzips DNA), DNA polymerase (adds nucleotides), and DNA ligase (joins fragments)

    • Differences in DNA, RNA, and protein: DNA stores genetic information, RNA is a messenger, proteins perform most functions in cells

    • James Watson: discovered the structure of DNA in 1953

    • Francis Crick: best known for his work with James Watson to identify the structure of DNA in 1953

    • Rosalind Franklin: recognized for her discovery of DNAs double helix structure through her X-ray images, Photo 51

  • Understand transcription

    • Role of RNA polymerase and the promoter: RNA polymerase binds to promoter region ”

  • Understand transcription

    • Role of RN

  • Understand transcription

    • Role of RNA polymerase and the promoter: RNA polymerase binds to promoter region ”

  • Understand transcription

    • Role of RN”

  • Understand transcription

    • Role of RNA polymerase and the promoter: RNA polymerase binds to promoter region ”

  • Understand transcription

    • Role of RN”

  • Understand transcription

    • Role of RNA polymerase and the promoter: RNA polymerase binds to promoter region ”

  • Understand transcription

    • Role of RN”

  • Understand transcription

    • Role of RNA polymerase and the promoter: RNA polymerase binds to promoter region ”

  • Understand transcription

    • Role of RN”

  • Understand transcription

    • Role of RNA polymerase and the promoter: RNA polymerase binds to promoter region ”

  • Understand transcription

    • Role of RN”

  • Understand transcription

    • Role of RNA polymerase and the promoter: RNA polymerase binds to promoter region ”

  • Understand transcription

    • Role of RNA polymerase and the promoter: RNA polymerase binds to promoter region to initiate transcription

    • Where does each occur in the cell?: Transcription occurs in the nucleus

  • Translation

    • How it works: mRNA is translated into a polypeptide chain at ribosomes

    • Role of the three types of RNA:

      • mRNA: Carries genetic information from DNA

      • tRNA: Brings amino acids to the ribosome

      • rRNA: Forms the ribosomal structure and catalyzes protein synthesis

    • How to read the universal codon table and build a polypeptide chain: Codons correspond to specific amino acids

  • Vocabulary:

    • Transcription: the process of making an RNA copy of a gene's DNA sequence.

    • Translation: the process by which cells use messenger RNA (mRNA) to create proteins

    • codon: a sequence of three nucleotides in a DNA or RNA molecule that codes for a specific amino acid or signals the start or end of protein synthesis

      ex: UUC - Phe

    • Mutation: Changes in the DNA sequence including types: substitution, insertions, deletions.

    • Insertions: a permanent change in a DNA sequence caused by the addition of nucleotides

    • deletion: the loss of genetic material in the form of a DNA sequence or a specific part of the chromosome

    • substitutions: a mutation that exchanges one base for another

    • start and stop codons: Indicators for the start and end of protein synthesis

    • Anticodon: tRNA's complementary sequence to mRNA

    • Polypeptide: Chain of amino acids resulting from translation

    • Ribosome: cellular structure that makes proteins

    • rER: a cell organelle that synthesizes and folds proteins for the cell

    • Nucleus: controls and regulates the cell's activities, including growth and metabolism

  • Write out the steps of gene expression:

    • DNA -> Transcription (mRNA synthesis) -> Translation (protein synthesis)

2. Traits and Disorders

  • Inherited traits and associated disorders:

    • Sickle Cell Anemia: Genetic disorder due to a mutation causing abnormal hemoglobin

    • Huntington's Disease: Autosomal dominant disorder causing neurodegeneration

    • Albinism: A group of genetic conditions marked by little or none of the pigment melanin in the skin, hair, and/or eyes.

    • PKU: a rare inherited disorder that causes an amino acid called phenylalanine to build up in the body

    • Tay Sacs: a rare inherited condition that mainly affects babies and young children. It stops the nerves working properly and is usually fatal.

    • Cystic Fibrosis: a disease that causes thick, sticky mucus to build up in the lungs, digestive tract, and other areas of the body

    • all inherited in an autosomal recessive pattern, meaning a person needs to inherit two copies of the mutated gene (one from each parent) to develop the disease

    • huntings is inherited in an autosomal dominant pattern where only one copy of the mutated gene is needed to cause the disease.

Page 3: Biotechnology and Evolution

1. Biotechnology

  • Recombinant DNA

    • Viral Vector: is a modified virus that delivers genetic material into cells

    • Plasmid Vector: a small, circular DNA molecule that's used to carry a specific DNA segment into a host cell

    • Role of Restriction Enzymes and Ligase: Cut DNA at specific sequences and join DNA fragments

  • Cloning

    • Write the steps of cloning your favorite cat

      • Isolate donor nucleus from somatic cell

      • Transfer nucleus into egg cell

      • Induce cell division to form an embryo

      • Implant embryo into a surrogate

  • Gene Therapy

    • Write the steps to making a GMO

      • Identify desired trait

      • Isolate the gene

      • Insert the gene into a vector

      • Transfer vector into host organism

  • Vocabulary:

    • CRISPR

      (short for “clustered regularly interspaced short palindromic repeats”) is a technology that research scientists use to selectively modify the DNA of living organisms.

    • PCR

      Polymerase chain reaction (PCR) is a laboratory technique that amplifies a specific DNA segment for analysis

    • RFLP

      Restriction fragment length polymorphism (abbreviated RFLP) refers to differences (or variations) among people in their DNA sequences at sites recognized by restriction enzymes.

    • DNA Fingerprinting

      a laboratory technique used to determine the probable identity of a person based on the nucleotide sequences

    • Gel Electrophoresis

      a laboratory method used to separate mixtures of DNA, RNA, or proteins according to molecular size

    • Genome

      the complete set of DNA, or genetic material, in an organism

    • Sequencing

      a laboratory technique that determines the order of bases in a DNA or RNA molecule

2. Evolution

  • Natural Selection

    • Explain how it works: Process by which individuals with favorable traits are more likely to survive and reproduce

  • Genetic Drift

    • the change in frequency of an existing gene variant in the population due to random chance

  • Gene Flow

    also called migration — is any movement of individuals, and/or the genetic material they carry, from one population to another

  • Mutation

    a change in the DNA sequence of a cells

  • Microevolution

    • Calculate Allele Frequencies: p + q = 1 for a two-allele system

    • When does it show that a population has evolved?: If they differ from generation to generation

  • Macroevolution

    • Taxonomy: The classification of organisms

    • What are the 8 taxa?: Domain, Kingdom, Phylum, Class, Order, Family, Genus, Species

  • Evolution of Animals

    • What are the 9 phyla?: Cnidaria, Porifera, Nematoda, Platyhelminthes, Chordata, Annelida, Arthropoda, Mollusca and Echinodermata.

    • What defines each phyla?: Porifera

      The most basic phylum, which includes sea sponges

    • Cnidaria

    Includes jellyfish, corals, and sea anemones

  • Platyhelminthes

    Flatworms that are known for their regeneration abilities

  • Nematoda

    Roundworms, some of which can be parasitic to humans

  • Annelida

    Segmented worms, like earthworms and leeches, that are known for their propensity for regeneration

  • Arthropoda

    The largest animal phylum, which includes insects, spiders, crabs, and centipedes

  • Mollusca

    Soft-bodied animals, like snails, slugs, octopi, and squid, which can have very complex nervous systems

  • Echinodermata

    Includes sea stars, sea urchins, and sea squirts

  • Chordata

    Includes vertebrates like fish, amphibians, reptiles, birds, and mammals

  • Evolution of Plants

    • What are the 4 phyla?: Bryophyta, Pteridophyta, Coniferophyta, Angiospermae

    • What defines each phyla?: Bryophyta (mosses), Pteridophyta (ferns), Gymnosperms (cone-bearing seed plants), and Angiosperms (flowering seed plants).