Cell and Cell Cycle

• Somatic cells

  • Body cells
  • Two copies of the genome
  • Diploid
• Germ cells

  • Sperm cell, Egg cell
  • One copy of the genome
  • Haplold
• Stem cells

  • Diplold
  • Divide to give rise to differentiated cells and replicate themselves through self-renewal
• 4 Specialized Types of Cell

  • Connective
  • Epithelium
  • Nervous
  • Muscle
• Domains of Life

  • Archaea and Bacteria - unicellular prokaryotes
  • Eukarya - unicellular and multicellular eukaryotes
• 4 Chemical Constituents

  • Carbohydrates
  • Lipids
  • Proteins
  • Nucleic Acid
• Examples of Carbohydrates

  • Sugar
  • Starches
• Examples of Lipids

  • Fats
  • Oils
• Examples of Protein

  • Antibodies
  • Enzymes
• Examples of Nucleic Acid

  • DNA
  • RNA
• Generalized Animal Cell

  • Surrounded by the plasma membrane
  • Contains Intracellular organelles
• Organelles

  • Divide labor by parlilioning certain areas or serving specific functions
  • Keep related biochemicals and structures close to one another to interact efficiently
• Cell Nucleus

  • Prominent organelle of the cell
  • Nerve center or control center of cell
  • Surrounded by a layer of nuclear envelope
• The Cell Nucleus contains:

  • Nuclear pores
  • Nuclear lamina (inner layer)
  • Nucleolus
  • Other contents: Chromosomes, RNA and nucleoplasm
• Secretion

  • Release of a substance from a cell
  • Begins when body sends a biochemical message to a cell producing a new substance
• Endoplasmic Reticulum (ER)

  • Interconnected membranous tubules and sacs where most protein synthesis occurs
  • Winds from the nuclear envelope to the plasma membrane
• Rough Endoplasmic Reticulum (ER)

  • protein synthesis
  • contains ribosomes
• Smooth Endoplasmic Reticulum (ER)

  • does not contain ribosomes
  • lipid synthesis
• Golgi Apparatus

  • Stack of interconnected flat, membrane-enclosed sacs
  • Processing center that adds sugars forming glycoproteins and glycolipids
  • packing center of the cell
  • proteins will be folded here
  • will release a vesicle through exocytosis
• Vesicles

  • Membrane bounded sac like organelles which pinch off from the tubular endings of the membrane
• Peroxisomes

  • Sacs with outer membranes studded with several types of enzymes
  • Break down lipids, rare biochemicals
• Lysosomes

  • Membrane-bound sacs containing 43 types of digestive enzymes
  • Dismantle bacterial remnants, worn-out organelles, and excess cholesterol
  • Engages in autophagy (cell's disposing its own trash; eating self)
• Mitochondria

  • Provide energy (in the form of ATP) by breaking the chemical bonds that hold logether the nutrient molecules in food
  • Surrounded by two membranes (inner and outer)
  • Cristae: folds of the inner membrane
• Plasma Membrane

  completely surrounds the cell and monitors the movements of molecules in and out

  • Chemical composition determines which substances can enter or leave the cell
• Plasma Membrane (Double layer (bilayer))

  • Phospholipids (fat molecule attached to a phosphate group)
  • Hydrophilic - Phosphate end
  • Hydrophobic - 2 chains of fatty acid
• Proteins aboard lipids

  • Contribute to cell's identity
  • Transport molecules
  • Keep out toxins and pathogens
• Receptors

  • molecules that extend from the plasma membrane (fit and specific)
  • to receive the molecules
• Ligands

  • molecules that bind lo the receptor; may cause chemical reactions inside the cell that carries out a particular aclivity
  • molecules that needs to enter the cell
• Cell to Cell Communication

  Signal Transduction

  • Molecules of the plasma membrane form pathways that detect signals from outside the cell and transmit them inward
• Cell to Cell Communication

  Cellular adhesion

  • plasma membrane helps cells attach to certain other cells forming connections then tissues
• Cytoskeleton

  • Meshwork of protein rods and tubules
  • Cell's architecture, positioning organelles and providing overall 3D shape
  • Transport organelles, cellular contents, and motor molecules
• 3 major types of proteins in Cytoskeleton:

  • Microtubules
  • Microfilaments
  • Intermediate Filaments
• Microtubules

  • maintain cellular organization and enable transport of substances within the cell
  • form hairlike structure called cilia
• Cilia

  • ”cell’s eyelashes“
  • 2 types of Cilia:
  • motile cilia that move
  • primary cilia that do not move but serve a sensory function
• Microfilaments

  • Long, thin rods composed of Actin
  • Solid and narrower than microtubules
  • Stretching and compression
  • Proteins when absent can cause diseases.
• Intermediate filaments

  • Composed of different proteins in cell types
  • Consist of paired proteins entwined into nested colled rods.
  • Abundant in skin cells and nerve cells.
• Growth, development, maintaining health, and healing from disease or injury require an intricate interplay between the rates of Mitosis and Cytokinesis
• Mitosis and Cytokinesis

  • Cell Division
• Apoptosis

  • "programmed cell death"
• CELL CYCLE

  • The sequence of activities as a cell prepares to divide.
  • Cell lining of the small intestine - divides throughout life.
  • Nerve cell - cannot divide
  • Cells in deepest skin layer - divides as long as the person is alive
  • Cell cycle is continuous.
  • 2 major stages: Interphase and Mitosis