lo 10 retake

• What is a gene?

  Segment of DNA that codes for a protein
• What is the function of many non-coding genes?


  Regulate expression of non protein coding genes
• Eukaryotic chromosomes are ___ and they usually have ___ of them

  Linear; More than one
• Prokaryotic chromosomes are ___ and they usually have ___ of them

  Circular; One
• What is chromatin?

  DNA double helix wound around histone proteins
• What are the functions of histone proteins?

  Prevent DNA from getting tangled and help regulate gene expression
• What is a nucleosome?

  DNA packed tight together and wrapped around histones
• The basic structural unit of chromatin is the ___

  Nucleosome
• The two main components of the cell cycle are ___ and ___

  Interphase; Mitosis
• What is happening during interphase?

  Cell is growing and preparing to divide
• What happens during mitosis?

  Division of the nucleus
• What are the two parts of M phase?


  Mitosis; Cytokinesis
• Mitosis results in two identical daughter ___

  Nuclei
• What happens during cytokinesis?

  Division of the cytoplasm
• Cytokinesis results in two identical daughter ___

  Cells
• What happens during G1?

  The cell grows and prepares for S phase
• If a cell is said to be in G0, then what do you know about the cell?

  Cells do not divide
• List three cell types that a G0 cell could be?

  Animal blood cells; Neurons; Muscle cells
• Which things are synthesized during S phase?

  Histone proteins
• Give an example of one thing that happens during G2?


  Checks newly synthesized DNA for errors
• What event marks the beginning of prophase?

  First stage of mitosis
• During prophase, each chromosome is comprised of two identical ___ ___

  Sister chromatids
• What is a chromatid?

  Chromosome that is temporarily attached to an identical chromatid
• Each chromatid is comprised of how many DNA double helicases?

  One
• List three events of prophase other than chromatin condensation?

  Mitotic spindle forms

  Microtubules attach to proteins

  Nuclear envelope begins to fragment
• What is the mitotic spindle made from?

  Microtubles
• Where does the mitotic spindle originate in a cell?


  Centrosome
• What do the spindles attach to during mitosis?


  Proteins called kinetochores
• Which event marks the beginning of prometaphase?

  Fragmentation of the nuclear envelope
• What happens during prometaphase?

  MIcrotubles attach to sister chromatids and gradually move chromosomes towards the center
• As a result of chromosome movement during prometaphase, sister chromatids end up attached to spindle fibers that are from ___ ends or poles of the dividing cell

  Opposite
• Where are the chromosomes during metaphase?


  Middle of the cell
• Which event marks the beginning of anaphase?

  Sister chromatids start to seperate
• Sister chromatids are pulled to ___ poles because the microtubules of the spindle fiber ___ and because the cohesin proteins that hold them together at their centromeres start to ___

  Opposite; Shorten; Dissociate
• Telophase returns the dividing cell to conditions that are present during ___

  Interphase
• List three events of telophase

  Nuclear envelope reforms

  Chromosomes decondense

  Microtubules are disassembled
• What is the structure called that separates the daughter cells during cytokinesis in animals and fungi?


  Contractile ring
• What is the contractile ring made from?

  Microfilaments and myosin
• How does the contractile ring work?

  Filaments slide past each other causing the ring to contract and separate
• In plant cells, the cell plate is formed from ___ that are produced by the Golgi?

  Membrane vesicles