Card Set Information

2012-10-08 14:27:57

study for exam 1
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  1. What is the largest object in the cell, and is whereDNA, the main genetic material is stored?
  2. What two membranes are the nucleus surrounded by?
    nuclear membrane or nuclear envelope
  3. What are large openings through the envelope thatallow cytoplasmic material (like proteins) to enter and nuclear products (likeribosomes) to exit the nucleus?
    Nuclear pores
  4. What is inside the nucleus?
    nucleolus, chromatin, and enzymes to make RNA and DNA
  5. What is a dark region within the nucleus; it is an area of intense ribosome synthesis and assembly?
  6. ______ is what chromosomes are made of.
  7. Sections of the DNA molecule can be copied tomake RNA – these sections are called?
  8. Two copies of the same DNA molecule are called?
    chromatids or sister chromatids
  9. The two ends of the chromosome/DNA molecule are called?
  10. After replication, the cell has twice as muchDNA as it did before replication, but it still has only 46 chromosomes.  Why?
    This is because both copies of a chromosome areconnected by a common centromere.
  11. Each telomere acts as a “cap” on the end to prevent chromosomes from sticking together – the telomere does not contain genes.
  12. Most complex organisms are built of ___  ____, which means each cell actually has 2 sets of chromosomes.
    diploid cells
  13. Each chromosome in a set is __________ with one of the chromosomes in the other set - two chromosomes that are ________ are the same size and shape, and both contain the same genes at thesame place on the DNA molecule
  14. Of the23 pairs of homologous chromosomes in humans, 22 pairs are ______ and do not determine sex.
  15. The ____ ____ is the period from the time a new cell is formed until it finishes dividing to form 2 new cells (20minutes for some bacteria, years for some human cells).
    cell cycle
  16. For most cells in the body, the cycle is divided into _______(the period between nuclear divisions) and _____(one type of nuclear division; the cell itself usually divides while thenucleus is dividing).
    Interphase; mitosis
  17. Most of the cell cycle is spent in ________ –this is when most cell metabolism occurs.
  18. What is Interphase made up of?
    G1, S Phase, and G2
  19. What is the period of growth following cell division?
  20. What is it called when the DNA is replicated in preparation for cell division?
    S Phase
  21. What is the second period of growth prior to next mitosis?
  22. During each of these stages these is at least one ________– a period when the decision is made to either continue progressing towards cell division, or to stop for a while and carry out neededDNA or cell repairs or processes.
  23. What is accomplished when a cleavage furrow (contractilering of cytoskeleton actin and myosin) gradually "pinches thecell in half"?
    Cell or cytoplasmic division (cytokinesis)
  24. What can be either mitosis or meiosis?
    Nuclear division (karyokinesis)
  25. _____is how most cells in your body divide and multiply.
  26. ______is how sperm and egg cells are formed.
  27. What type of nuclear division produces 2 daughter nuclei, identical to each other and to the orginal parent nucleus?
  28. Which type of nuclear division produces 4 genetically different nuclei (or cells) with only 23 chromosomes each, or half the normal chromosome number?
  29. What type of cell has only one set of chromosomes? And what are the examples in the human body?
    haploid;  sperm and egg cells
  30. What are the steps of nuclear division?
    • Prophase
    • Metaphase
    • Anaphase
    • Telophase
  31. What is the most common type of nuclear division?
  32. Which step of nuclear division is this? Chromosomes condense and become visible, nuclear membranes and nucleolus disappear,  microtubules assemble to form spindle apparatus
  33. Which step of nuclear division is this? Chromosomes line up across cell equator on metaphase plate, chromosomes can be counted.
  34. Which step of nuclear division is this? Chromatids are separated and one chromatid is pulled to each pole (opposite sidesof cell) – pulling is done by microtubules of spindle.
  35. Which step of nuclear division is this? Nuclei reform, chromosomes and spindledisappear, cell divides.
  36. What are the subunits of nucleic acids?
  37. What are the nitrogenous bases found in DNA?
    • Adenine
    • Thymine
    • Guanine
    • Cytosine
  38. What are the nitrogenous bases found in RNA?
    • Adenine
    • Uracil
    • Guanine
    • Cytosine
  39. Guanine always base pairs with?
  40. Adenine always base pairs with?
    Thymine or Uracil
  41. The DNA molecule is actually a ____-_____ ______, with the two strand sheld together by hydrogen bonds between the complementary bases of the two strands.
    double-stranded polymer
  42. Each gene carries a sequence of bases that will be copied to make one ____.
  43. An ____ molecule is a single-strandednucleic acid.
  44. DNA synthesis is called ____ ______, and only occurs during S phase. 
    DNA replication
  45. New nucleotides will pair up with the exposed bases, and an enzyme (____ _____) will covalently bond the nucleotides into a new DNA strand.
    DNA polymerase
  46. DNA polymerase not only builds new DNA, it also ______-______ as it builds, and should a mispairing occur (A with G), it will removethe incorrect base and add the right one.
  47. DNA polymerase can also repair damaged DNA during interphase, and is called the "____-_____ _____ _______."
    error-proof repair system
  48. What special enzyme is required to replicate the telomere?