Science: Biology

• Which among the choices is a Prokaryote?

  Archea
• Cell


  The smallest living unit in all organisms
• Modern cell theory

  1. The cell is the smallest living unit in all organisms
  2. All living things are made of cells
  3. All cells come from other, pre-existing cells
• Unicellular


  A single-celled organism
• Multicellular


  Organisms made of many cells
• Types of cells

  • Prokaryotes
  • Eukaryotes
• Prokaryotes


  • Have no nucleus

  Have no membrane bound organelles
• Eukaryotes


  • Have membrane bound organelles
• Cytoplasm


  Jelly-like material that surrounds internal cell structures
• Cytoskeleton


  Collection of fibers that provide support and play a role in cell movement
• Ribosomes


  Organelles that make proteins
• Nucleus


  Holds the genetic material (DNA) and controls cell activities
• Nucleolus


  Where ribosomes are produced
• Endoplasmic reticulum (ER)


  Processes and transports molecules

  Rough ER has ribosomes attached, smooth ER does not
• Golgi apparatus


  Packaging and sorting center for molecules
• Mitochondria


  Power plant that makes ATP energy through cellular respiration
• Chloroplasts


  Organelles in plant cells that make glucose through photosynthesis
• Vacuoles


  Storage organelles, larger in plant cells
• Cell wall


  Additional layer in plant cells that offers protection and shape maintenance
• How a protein gets out of the cell

  Instructions from DNA

  Made by ribosomes

  Transported through ER and Golgi

  Secreted through the cell membrane
• Mitosis is a type of cell division done by most of your body cells and it's really important for your cells to divide
• Mitosis

  The process that allows cells to grow and repair damage
• The process that makes sperm or egg cells, that is called meiosis
• Mitosis


  Produces identical body cells
• Cells are not dividing all the time, they spend most of their time in DNA Replication, Translation and Transcription or also called
• Chromosomes


  Condensed units of DNA and protein found in the nucleus
• Humans have 46 chromosomes in their body cell nuclei
• Cytokinesis is responsible for the final separation into two cells by splitting the cytoplasm, completing the mitosis process
• Meiosis

  A process that contributes to genetic variety, makes sperm and egg cells (gametes)
• Interphase


  Cell is growing, replicating DNA, carrying out cell processes, happens before meiosis and mitosis
• Chromosomes

  Humans have 46 chromosomes in body cells, sperm and egg cells have 23 chromosomes each
• Meiosis

  • A reduction division, starting cell has 46 chromosomes, ending cells have 23 chromosomes
• Interphase before meiosis

  Cell has 46 chromosomes, DNA replicates so now has 92 chromatids but still counted as 46 chromosomes
• Prophase I


  • Chromosomes condense and thicken, line up in homologous pairs, crossing over occurs
• Homologous chromosomes


  Approximately the same size, contain the same types of genes in the same locations
• Crossing over


  Chromosomes in homologous pairs exchange genetic information, creates recombinant chromosomes
• Metaphase I


  Chromosomes in pairs in the middle of the cell
• Anaphase I


  Chromosomes pulled away by spindle fibers
• Telophase I


  Two newly formed nuclei, cytoplasm splits (cytokinesis)
• Prophase II


  Chromosomes, no homologous pairs, no crossing over