Cell Biology Flashcards

Cell Cycle

• Cell Cycle: Continuous process of growth and replication of cells.
• Interphase: Portion of the cell cycle where growth is initiated and DNA is replicated.
• Mitosis: Portion of the cell cycle where the cell divides its replicated DNA among two identical daughter cells.

Matching Definitions

• Phospholipid Bilayer:
  • A double layer of phospholipids.
  • Nonpolar fatty acid tails line up facing each other.
  • Polar phosphate heads line up to face the water-containing environments of the cell.
• Cytoplasm:
  • Region between the plasma membrane and the nuclear membrane.
  • Contains the cytosol, cytoskeleton, and organelles.
• Nucleus:
  • Control center of the cell.
  • Contains the cell’s DNA.
• Nucleolus:
  • Area within the nucleus.
  • Responsible for RNA and ribosome production.
• Mitochondrion:
  • Site of most of the cell’s ATP (adenosine triphosphate) production.
• Ribosome:
  • Site of protein synthesis.
• Peroxisome:
  • Contains enzymes that detoxify chemicals such as hydrogen peroxide (\$H2O2\$).
• Smooth Endoplasmic Reticulum:
  • Series of membrane-enclosed spaces.
  • Site of lipid and cholesterol synthesis and metabolism.
  • Involved in drug and toxin detoxification.
• Rough Endoplasmic Reticulum:
  • Series of membrane-enclosed spaces.
  • Modifies proteins made by the ribosomes.
• Golgi Apparatus (or Complex):
  • Group of membrane-bounded sacs.
  • Modifies and packages proteins for export or use within the cell.
• Lysosome:
  • Vesicular organelle.
  • Contains digestive enzymes that break down different substances within the cell.
• Centriole:
  • Paired organelles composed primarily of microtubules.
  • Appear to be microtubule organizing centers.
  • Important in facilitating the assembly and disassembly of microtubules.
• Cilia:
  • Hairlike extensions from the plasma membrane.
  • Propel substances past the cell.
• Flagella:
  • Single extension from a cell.
  • Propels the cell itself.
• Vesicle:
  • Series of membrane-enclosed spaces.
  • Modifies proteins made by the ribosomes.

Diffusion, Osmosis and Tonicity

• Diffusion: The movement of solute from a high concentration to a low concentration.
• Osmosis: The movement of solvent from a solution with a lower solute concentration to a solution with a higher solute concentration through a selectively permeable membrane.
• Tonicity: Comparative measure of the osmotic pressure of two solutions and the ability of one solution to cause water movement by osmosis from another solution.

Mitosis Phases

Prophase

• Events:
  • Chromatin threads condense to form chromosomes.
  • The nuclear membrane disappears.
  • The mitotic spindle forms, and visible spindle fibers attach to the chromosomes.
• Appearance:
  • Poorly defined nucleus.
  • Bar-like chromosomes.

Metaphase

• Events: Chromosomes line up in the center (or the equator) of the cell.
• Appearance: Dark line of chromosomes is visible down the middle of the cell.

Anaphase

• Events: The chromosomes separate and are pulled to the opposite poles of the cell by spindle fibers.
• Appearance: Separating, V-shaped chromosomes are visible with varying distances separating them.

Telophase

• Events:
  • A cleavage furrow forms and cytokinesis takes place as the cytoplasm and organelles are doled out to the daughter cells.
  • The chromosomes uncoil to form chromatin.
• Appearance:
  • The cell looks as if it is being pinched.
  • Distinct chromosomes are often not visible.
  • New nuclear membranes may be present.

Cell Cycle Parts

G1 Phase

• During this phase, the cell grows, synthesizes proteins, and is very metabolically active.

S Phase

• During the S phase, the cell replicates its DNA.

G2 Phase

• The G2 phase is characterized by the cell undergoing final preparations for cell division and cytokinesis. The cell manufactures enzymes and other proteins that are necessary for cell division to occur.

M Phase

• The M phase is where the cell undergoes mitosis, or cell division. The replicated DNA and cytoplasm are doled out to two new daughter cells, each of which are identical daughter cells.