Basic Cell Structure

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Basic Cell Structure
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Cells

• Basic building blocks of life
• Understanding of cell morphology is critical to
  the study of biotechnology

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Cell

• Smallest living unit of an organism
• Grow, reproduce, use energy, adapt, respond to
  their environment

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Cell

• Many cannot be seen with the naked eye
• A cell may be an entire organism or it may be one
  of billions of cells that make up the organism

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Cells

• Divided and classified in many ways
• One common classification method is the presence
  or absence of a cell necleus

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Nucleus

• Relatively large structure with a cell
• Directs cell activities
• Some simple single celled organisms lack a nucleus

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Nucleus

• Prokaryotes have no nucleus
• Eukaryotes have a nucleus

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Prokaryotes

• Single celled organism
• Kingdom Monera
• Lacks a cell nucleus
• Internal structure is less organized than other
  cells

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Prokaryotes

• Genetic info needed is within the cell
• Two most common blue green bacteria and true
  bacteria

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Blue green bacteria

• Have ability to produce their own food like
  plants
• Most bacteria get their food from other sources

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Prokaryotes

• Less complex than eukaryotes
• Still have many of the basic internal
  characteristics

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Common prokaryote structures

• Cytoplasm
• Chromosomal material
• Cell membrane and wall
• Ribosomes
• Some have flagellum for mobility

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Eukaryotes

• Organism made up of cells that have a nucleus
• May be single celled Kingdom Protista
• May have billions of cells like plant and animal
  kingdoms

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Eukaryotes

• Single celled eukaryotes include paramecia,
  euglena, and diatoms

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Eukaryotes

• Typically are highly organized
• Infinite number of shapes and purposes

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Eukaryotes

• Human body has at least 85 different cell types
• All eukaryotes have a number of structures in
  common

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Common structures

• Organelles smaller parts of the cell with
  specific funtions
• Cell membrane acts as a gatekeeper

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Cell membrane

• Controls what enters and leaves the cell
• Plants, algae and bacteria typically have a
  tough outer structure known as a cell wall

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Cell wall

• Provides additional structure and protects the
  cell from pressure caused by movement of water
• Animal cells do not have walls

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Cytoplasm

• Organelles are surrounded by a jelly like
  substance
• Primary component is water

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Nucleus

• Largest and most identifiable part of the cell

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Other organelles

• Ribosomes
• Mitochondria
• Golgi bodies
• Endoplasmic reticulum

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Other organelles

• Lysosomes
• Vacuoles
• Chloroplasts in plants

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Nucleus

• Brain of the cell
• Site of much of the manipulation done in
  biotechnology

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Nucleus

• Controls activity of the cell
• Round or oval structure
• Typically found in the middle of the cell
• Appears darker than surrounding material

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Nucleus

• Surrounded by a membrane that controls passage of
  materials in and out of the area

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Nucleus

• Contains DNA
• DNA is located on chromosomes
• Most organisms are diploid have tow chromosomes
  for each trait

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Diploid

• Humans 23 pair
• Goldfish 90 chrms, 45 pair

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Cytoplasmic Organelles

• Organelles are required for proper cell function
• Ribosome make proteins for cellular use and
  communication
• May be attached to endoplasmic reticulum

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Endoplasmic reticulum

• Layered membraneous
• Make and transport proteins

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Vacuole

• Large organelle, without specific shape
• Store waste or raw materials used in synthesis of
  proteins

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Golgi Bodies

• Golgi apparatus
• Similar to endo. Ret.
• Look like a thick elastic band that has been
  folded several times

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Golgi Bodies

• Adds modifications to unfinished proteins
• Makes lysosomes

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Lysosome

• Small round
• Store enzymes that break down food into chemical
  compounds
• Destroy cell organelles and the cell itself

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Mitochondria

• Energy factories
• Rod shaped
• Change food into molecules that can be used for
  energy

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Mitochondria

• Contain DNA
• Can replicate themselves

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Chlorplast

• Found in plants and some other organisms
• Contain chlorophyll

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Cellular processes

• Respiration
• Osmosis
• Diffusion
• Photosynthesis

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Respiration

• Cells break down carbohydrates and other
  molecules to produce energy
• Oxidation of glucose is one of most common forms

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Respiration

• Breaking down of sugar into water, carbon
  dioxide, and energy
• Energy is used to do the work of the cell

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Osmosis Diffusion

• Transport of raw materials, wastes, and
  synthesized materials out of the cell

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Diffusion

• Movement of molecules, especially gases and
  liquids from areas of high concentration to areas
  of low concentration

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Osmosis

• Specific type of diffusion
• Movement of water through a membrane from areas
  of high concentration to areas of low
  concentration

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Equilibrium

• Diffusion and osmosis happen to enable a cell to
  reach equilibrium

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Cellular reproduction

• Three ways
• Fission
• Mitosis
• Meiosis

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Fission

• Prokaryotes
• Cell grows larger and makes a second copy of its
  DNA
• At some point the cell membrane divides the cell
  by the growth of a transverse septum

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Fission

• Two new cells are formed as the division grows
  inward from either side of the cell
• Two cells now called daughter cells
• Sometimes known as binary fission

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Mitosis

• Eukaryotes
• Requires 6 stages
• Interphase, prophase, metaphase, anaphase,
  telophase, cytokinesis

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Mitosis

• Creates cells that are identical to the original
  cell.
• Have the entire compliment of chromosomes
  existing in pairs - diploid

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Meiosis

• Division of sex cells
• Stages of Meiosis I Interphase I, prophase I,
  metaphase I, anaphase I, telophase I, cytokinesis
  I

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Meiosis

• Meiosis II
• Interphase II, prophase II, metaphase II,
  anaphase II, telophase II, cytokinesis II

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Meiosis

• Each cell receives one chromosome from each pair
  randomly
• Resulting cells have half the normal number of
  Chromosomes - haploid