DNA and Cell Cycle Review

Enduring Understandings
  • [ ] All cells contain DNA
  • [ ] DNA contains regions called genes
  • [ ] Species’ characteristics are carried into DNA
  • [ ] DNA replication is usually very accurate, but errors can occur
  • [ ] Errors in DNA replication can result in mutation
  • [ ] Mutation can be a sours of genetic variation
  • [ ] Sexual reproduction leads to genetic diversity due to the random assortment of chromosomes associated with sperm and egg cells of the individuals possessing them and reproducing,
Essential Questions
  • [ ] How does the structure of DNA determine the structure of a protein?
    • [ ] The sequence of basis on the DNA molecule is what directs the sequence of amino acids in the protein molecule, linking it together.
    • [ ] The sequence of bases in DNA codes for the sequence of amino acids of a protein.
  • [ ] How does mitosis play a role in the growth and repair of multicellular organisms?
    • [ ] In the case of multicellular organisms, mitosis helps in growth and repair by producing more number of identical cells.
    • [ ] For example plants, animals depend on cell division for their growth by addition of new cells.
  • [ ] Why does sexual reproduction lead to variation and genetic traits?
    • [ ] Sexual reproduction has the potential to produce tremendous genetic variation in offspring, because of independent assortment and random union of gametes during fertilization.
  • [ ] How can mutations occur and how can they lead to genetic diversity?
    • [ ] Changes to an individual's DNA are called mutations .
    • [ ] Mutations can arise when mistakes are made while cells are copying DNA, like making a spelling mistake when copying a word.
    • [ ] These mutations make up a species' genetic diversity. Over generations, more and more mistakes are made, leading to more mutations.
Essential Vocabulary
  1. Inheritance: passing of traits from parent to offspring via reproduction
  2. DNA: nucleic acid containing genetic info for cell growth, function and division
  3. Nucleotides: building blocks of RNA/DNA
  4. Nitrogen Bases: in the interior of DNA, bases with hydrogen

     1. Adenine 2. Thymine 3. Guanine 4. Cytosine

  1. DNA Replication Associated Enzymes: enzymes which propel DNA replication

     1. DNA Polymerase 2. Ligase 3. Helicase

  1. Semi-conservative: some old material, some new material
  2. Mutations: change in the DNA sequence of an organism
  3. Chromosomes: x-shaped substance containing DNA and proteins, 23 per cell
  4. Genes: basic unit of heredity passed on from parent to child
    1. Proteins: molecule made up of amino acids
    2. Trait: specific characteristics determined by genes or the environment
    3. Genetic Variation: differences in DNA sequences between people of a population
    4. Cell Cycle: series of events of a cell as it grows and divides
    5. Mitosis: part of cell cycle where replicated cells separate individually
    6. Cancer: disease where abnormal cells divide uncontrollably and destroy body tissue
Practice Questions
  • What are the parts of a nucleotide, and what are their drawn shapes?
    • Phosphate group: circle
    • Deoxyribose sugar: pentagon
    • Nitrogen base: rectangle
  • What are the DNA base pairing rules?
    • Adenine pairs with Thymine
    • Guanine pairs with Cytosine
  • What shape is DNA?
    • A double helix
  • What is the function of DNA?
    • DNA holds genetic information/code
  • DNA vs RNA
    • DNA: Deoxyribonucleic Acid
    • double stranded
    • structured into chromosomes
    • deoxyribose: sugar
    • uses thymine
    • is read by polymerases
    • stores genetic information
    • can self-replicate
    • lasts for a long time
    • it is read 3’→ 5
    • RNA: Ribonucleic Acid
    • single stranded
    • ribose: sugar
    • modified 5’ cap and 3’ poly-A tail
    • uses uracil
    • stores information about protein structure
    • read by ribosomes
    • can have multiple structures (i.e. mRNA)
    • doesn’t usually last for a long time
    • it is read 5’→ 3
    • BOTH
    • uses adenine, cytosine, and guanine
    • has sugar and a phosphate
  • What is the relationship between DNA, a gene, a chromosome, and a protein?
    • DNA+protein=chromosome
    • Genes are segments of DNA
  • DNA replication is semi-conservative, what does that mean?
    • Half new DNA, half old DNA (maintains identical status)
  • What is the purpose of DNA replication?
    • To produce 2 new identical DNA molecules
    • Either to asexually reproduce or to repair
  • What is the role of the molecules in the process of DNA replication?
    • Helicase: breaks through Hydrogen bonds that hold DNA strands together
    • RNA Polymerase: copies DNA sequence into an RNA sequence
    • DNA Polymerase: replicates DNA to build a new strand of DNA
    • Ligase: glues DNA fragments together
  • What are the steps of the cell cycle?
    • Interphase: absence of cell division, motives of sub-phases
    • G1: major period of cell growth
    • S: synthesis/replication
    • G2: rapid growth to prepare to mitosis
    • Mitosis: cell duplicates and separates
    • Cytokinesis: the splitting of the two new daughter cells
  • Which part of the cell cycle do cells spend the most time in?
    • Interphase. It has multiple sub-phases and needs to grow the cell, replicate its chromosomes, and prepare the cell for subdivision.
  • What are the steps of Mitosis?
    • Prophase: two circles--one with strings, one with wisps and dots
    • Chromosomes condense, become visible, membrane dissolves, fibers form+ interact with chromosomes
    • Metaphase: one circle--with football shapes lines
    • Copied chromosomes align in middle, spindle fibers attach to each of them
    • Anaphase: 2 connected circles with v's apart, one lone circle with “succulents” one each side
    • Chromosomes move to opposite ends of the cell, by the end two equal groups form
    • Telophase: 2 circles with wispier strings
    • Chromosomes unravel into chromatin spread throughout the new cell, by the end, membrane forms
  • What is the purpose of mitosis?
    • To create two new identical cells to replace or reproduce asexually via cell division
  • What is cell differentiation
    • Process where immature unspecialized cells take on individual characteristics and reach their mature, specialized form; caused by gene expression changes
  • What is a mutation?
    • A genetic mistake, change in the DNA sequence of a cell
  • What are some things that could cause mutations
    • Errors in DNA replication
    • Regulators working wrong during replication
    • Absence of materials
    • Negative environmental factors