classical genetics

• Genome - before any cell divides by binary fission, mitotically, or meiotically—it must first duplicate its entire ---, which consists of all of the cell’s genetic material
• DNA - is a double-stranded nucleic acid. Each strand of the double helix is composed of nucleotides
• DNA does not, however, replicate by itself. Instead, an army of enzymes copies DNA just before a cell divides
• DNA polymerase - is the enzyme that adds new DNA nucleotides that are complementary to the bases on each exposed strand.
• label

  A) nucleotide

  B) replication

  C) dna polymerase

  D) helicase enzyme

  E) dna molecule

  
• ligase - enzymes form covalent bonds between adjacent DNA segments
• In prokaryotes, reproduction occurs by binary fission, an asexual process that replicates DNA and distributes it (along with other cell parts) into two daughter cells
• Mitosis - Divides a eukaryotic cell’s genetic information into two identical nuclei
• Meiosis - Divides a eukaryotic cell’s genetic information into genetically unique nuclei
• Cytokinesis - Distributes the cytoplasm into two daughter cells following division of a cell’s chromosomes
• label

  A) sex pilus

  B) dies

  C) chromosome fragment

  
• Eukaryotic chromosomes consist of chromatin, which is a collective term for all of the cell’s DNA and its associated proteins.
• Chromatin - DNA and its associated proteins
• Chromosome - A single continuous molecule of DNA wrapped around protein. Eukaryotic cells contain multiple linear chromosomes, whereas bacterial cells typically have one circular chromosome.
• Chromatid - One of two identical attached copies that make up a replicated chromosome
• Centromere - A small region of a chromosome where sister chromatids attach to each other
• mutation - is a change in the DNA sequence of an organism.
• That is, the base adenine (A) pairs with thymine (T), whereas cytosine (C) forms complementary base pairs with guanine (G).
• chromatin is organized into nucleosomes, each consisting of a stretch of DNA wrapped around eight proteins (histones)
• Two chromatids make up the replicated chromosome.
• Because these paired chromatids have identical DNA sequences, they are called

  “sister chromatids.”
• label

  A) centromere

  B) replicated chromosome

  C) histones

  D) nucleosome

  E) identical sister chromatids

  
• label the cell cycle

  A) s phase

  B) g2 phase

  C) g1 phase

  D) mitosis

  
• Interphase - is the interval between successive cell divisions; protein synthesis, DNA replication, and many other events occur
• mitosis - during which the contents of the nucleus divide.
• cytokinesis -the cell splits into two daughter cells.
• G1 phase - the cell grows, carries out its basic functions, and produces the new organelles and other components it will require if it divides.
• S phase - enzymes replicate the cell’s genetic material and repair damaged DNA. each chromosome includes one DNA molecule. By the end of this, each chromosome consists of two attached sister chromatids.
• G2 phase - the cell continues to grow but also prepares to divide, producing the proteins that will help coordinate mitosis. The DNA winds more tightly around its associated proteins, and this event signals the start of mitosis. Interphase has ended.
• metaphase - the spindle lines up the chromosomes along the center, or equator, of the cell. This arrangement ensures that each cell will receive one copy of each chromosome
• anaphase - the centromeres split and some spindle fibers shorten as they pull the sister chromatids (now chromosomes) toward opposite poles of the cell. At the same time, other microtubules in the spindle lengthen in a way that moves the poles farther apart, stretching the dividing cell.
• Telophase - the final stage of mitosis, essentially reverses the events of prophase. The spindle disassembles, and the chromosomes begin to unwind. In addition, a nuclear envelope and nucleolus form at each end of the stretched out cell. As this phase ends, the division of the genetic material is complete, and the cell contains two nuclei—but not for long.
• Benign tumors - are usually slow-growing and harmless, unless they become large enough to disrupt nearby tissues or organs. A tough capsule surrounding the tumor prevents it from invading nearby tissues or spreading to other parts of the body.
• malignant tumor - invades adjacent tissue. Because it lacks a surrounding capsule, a --- is likely to metastasize, meaning that its cells can break away from the original mass and travel in the bloodstream or lymphatic system to colonize other areas of the body
• Cancer - begins when a single cell accumulates genetic mutations that cause it to break through its cell cycle controls.
• Asexual reproduction - generates virtually identical copies of an organism.
•  sexual reproduction - two parents produce genetically variable gametes by meiosis. Fertilization (the joining of two gametes) produces a zygote.
•  Mitotic cell division - produces identical eukaryotic cells used in growth, tissue repair, and asexual reproduction.
• Apoptosis - is programmed cell death. Both cell division and cell death occur throughout the normal development and life of a multicellular organism.
• Centrosome - Structure that organizes the microtubules that make up the spindle in animal cells