SCIENCE MASTERY TEST (ALL)

• Digestive System


  The system responsible for the mechanical and chemical breakdown of food to extract nutrients, minerals and energy to sustain the body
• Mouth


  1. Digestive process starts

  2. Chewing

  3. Saliva moistens food to help it move through esophagus into stomach
• Salivary glands


  • Make saliva, a digestive juice that moistens food
  • Contain an enzyme that breaks down starches
• Mechanical digestion


  Breakdown of food by physical means (e.g. chewing)
• Chemical digestion


  Breakdown of food by enzymes and acids
• Lingual lipase


  Enzyme that breaks down triglycerides to diglycerides and free fatty acids
• Salivary amylase (Ptyalin)


  Enzyme that breaks down starch to glucose and oligosaccharides
• Pharynx


  Hollow tube inside the neck that starts behind the nose and ends at the top of the trachea and esophagus
• Larynx


  Part of the respiratory system, a hollow tube that lets air pass through the throat to the trachea and lungs, also known as the voice box
• Esophagus


  Muscular tube that carries food and liquids from the mouth to the stomach
• Stomach


  1. shaped organ that digests food, produces enzymes and acids to break down food
• Intestine


  Long continuous tube running from the stomach, main function is to digest and absorb nutrients from food
• Small intestine


  Has three parts (duodenum, jejunum, ileum), absorbs nutrients, minerals and water
• Large intestine


  Long, tube-like organ connected to the small intestine at one end and the anus at the other, removes water and some nutrients/electrolytes from partly digested food
• Accessory organs of the digestive system

  • Teeth
  • Tongue
  • Salivary glands
  • Liver
  • Gallbladder
  • Pancreas
  • Appendix
  • Cecum
  • Rectum
  • Anus
• Teeth


  Break down food into smaller pieces to swallow more easily, incisors cut and gnaw, molars grind and chew
• Tongue


  Facilitates movement of food during chewing and swallowing, also involved in speech and taste
• Salivary glands


  Produce saliva to moisten food and contain the enzyme amylase to help break down starches
• Liver


  Removes toxins from blood, maintains healthy blood sugar levels, produces bile to help digest fats
• Gallbladder


  Small pear-shaped organ that stores and releases bile, common issue is gallstones
• Pancreas


  Long flat gland behind the stomach, plays a role in digestion and regulating blood sugar levels
• Appendix


  Sits in the lower right abdomen, function is unknown but may act as a storehouse for good bacteria
• Cecum


  Pouch that forms the first part of the large intestine, connects small intestine to the colon
• Rectum


  Collects and holds waste until it is time to be released from the body
• Anus


  Opening at the end of the digestive tract through which stool leaves the body
• The digestive system functions to provide mechanical processing, digestion, absorption of food, secretion of water, acids, enzymes, buffer, salt, and excretion of waste products
• Cell cycle


  Regular pattern of growth, DNA replication, and cell division
• Mitosis


  Process of cell duplication, or reproduction, during which one cell gives rise to two genetically identical daughter cells
• Meiosis


  Reduces the chromosome number by half, creating four haploid cells, each genetically distinct from the parent cell
• Stages of the cell cycle

  • Gap 1
  • Synthesis
  • Gap 2
  • Mitosis/Meiosis
• Interphase


  Cells spend the majority of their cell cycle in this phase, which is for cell growth
• Mitosis


  1. Includes division of the cell nucleus (mitosis) and division of the cell cytoplasm (cytokinesis)

  2. Chromosomes condense

  3. Nuclear membrane disappears

  4. Centrioles separate

  5. Spindle fibers form
• Metaphase


  1. Chromosomes line up across the center of the cell

  2. Spindle fibers connect the centromere of each sister chromatid to the poles
• Anaphase


  1. Centromeres that join the sister chromatids split

  2. Sister chromatids separate becoming individual chromosomes

  3. Separated chromatids move to opposite poles
• Telophase


  1. Chromosomes uncoil

  2. Nuclear envelope forms around the chromosomes at each pole

  3. Spindle fibers break down

  4. Cytokinesis begins
• Cytokinesis


  Division of the cytoplasm into two individual cells, differs in plant and animal cells
• Mitosis and Cytokinesis produce two genetically identical daughter cells
• Interphase prepares the cell to divide, during this phase the DNA is duplicated
• Meiosis


  Occurs in germinal cells, reduces the chromosome number by half to create four haploid cells
• Meiosis


  1. Crossing over occurs during Prophase I

  2. Recombinant chromosomes are formed