Cells

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Cells

• Chapter 7

http//faculty.clintoncc.suny.edu/faculty/Michael.
Gregory/files/Bio20100/Bio2010020Lectures/Cells
/cells.htm
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Many unicellular bacteria
Rhodospirillum rubrum
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Onion Cells - multicellular
http//faculty.clintoncc.suny.edu/faculty/Michael.
Gregory/files/Bio20100/Bio2010020Lectures/Cells
/cells.htm
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Elodea Cells - multicellular
http//faculty.clintoncc.suny.edu/faculty/Michael.
Gregory/files/Bio20100/Bio2010020Lectures/Cells
/cells.htm
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Human Cheek Cells
http//faculty.clintoncc.suny.edu/faculty/Michael.
Gregory/files/Bio20100/Bio2010020Lectures/Cells
/cells.htm
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Cell Theory

• Robert Hooke In 1665 he observed cork under a
  microscope
• Used the word cell to describe the structures
  with empty spaces he observed

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Robert Hookes Observations
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In the 1800s

• Robert Brown Discovered a central structure in
  cells we now call the nucleus
• Matthias Schleiden found that plants are made
  up of cells

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• Theodor Schwann found that animals are made up
  of cells
• These discoveries led to the development of the
  cell theory

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Cell Theory

• 1. All living things are made up of one or more
  cells.
• 2. Cells are the basic units of structure and
  function in living things.

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• 3. All cells come from other cells.

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Animal Cell
www.cellsalive.com
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2.2 Cell Parts and Their Jobs

• Cell Membrane
• gives the cell shape, holds the cytoplasm, and
  helps regulate what can go in and out of the cell

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Nucleus

• Controls most of cells activities
• Contains genetic information chromosomes made
  of DNA deoxyribonucleic acid
• Determines what proteins are made and when

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Nucleus
www.cellsalive.com
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Nuclear Membrane

• Surrounds the nucleus has pores that allow
  certain materials to move in and out of the
  nucleus

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Nucleolus

• Located inside of the nucleus
• Helps produce ribosomes

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Cytoplasm

• Clear, jellylike material between the cell
  membrane and the nucleus that makes up most of
  the cell
• Made mostly of water with some other chemicals

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Ribosomes

• Tiny organelles . Proteins are assembled at the
  ribosomes. Ribosomes are found throughout the
  cytoplasm and on the Rough Endoplasmic Reticulum.

www.cellsalive.com
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Mitochondria
www.cellsalive.com
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Mitochondria

• The Powerhouses of the cell because they
  produce energy from food that was digested
• ATP energy-storing molecule that is made in the
  mitochondrion

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Vacuoles
www.cellsalive.com
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Vacuole

• Liquid-filled space that stores water, food, and
  minerals
• Store wastes until cell gets rid of them

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Centrioles
www.cellsalive.com
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Centrioles

• Cell parts that help with cell reproduction
• Found in pairs
• In animal cells

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Plant Cell
www.cellsalive.com
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Chloroplasts
www.cellsalive.com
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Chloroplasts

• Contain the green pigment chlorophyll
• Chlorophyll can trap energy from the sun and use
  it for photosynthesis, so plants can make food

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Cell wall

• Found in cells of plants, algae, fungi, and
  bacteria
• A thick outer covering surrounding the cell
  membrane
• Provides support and protection

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Lysosomes

• Digestive sacs destroy worn out parts and get
  rid of bacteria contain digestive enzymes break
  down disease-causing germs

www.cellsalive.com
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Endoplasmic Reticulum
www.cellsalive.com
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Endoplasmic Reticulum

• Canal network moves materials within cell
• Its called rough ER when it has ribosomes on it
• Its called smooth ER when there are no ribosomes
  on it

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Golgi Apparatus
www.cellsalive.com
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Golgi Apparatus

• Packaging structure packages, modifies, and
  stores chemicals

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Cell Processes

• Passive Transport - The movement of substances
  across a cell membrane without the cell using
  energy

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• Passive transport - energy is not needed to move
  materials across a cell membrane - ex diffusion,
  osmosis, facilitated diffusion

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Diffusion

• the movement of molecules from an area of higher
  concentration to an area of lower concentration.

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• Occurs using the kinetic energy of the molecules.
  

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• Ability for molecule to diffuse across cell
  membrane depends on
• 1. Size of molecule
• 2. Type of molecule
• 3. Chemical nature of molecule

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Concentration gradient

• the difference in concentration of a substance
  across space

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• Molecules will change direction when they hit
  other particles or if there are no particles in
  the way, they will move to less concentrated
  areas.

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Equilibrium (dynamic)

• when the concentration of the molecules of a
  substance is the same throughout an area state
  in which no net change occurs even though there
  is random movement of molecules

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Osmosis

• The diffusion of water across a selectively
  permeable membrane

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• water moving from an area of greater
  concentration to a lower concentration across a
  selectively permeable membrane

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Hypertonic Solution

• a solution whose solute concentration is higher
  and water concentration is lower than that inside
  a cell water will move out of the cell if it
  placed in a hypertonic solution

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In salt water

• There are more water molecules inside the plant
  cell than outside, so water will move out of the
  plant cell the plant wilts

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Hypotonic Solution

• a solution whose solute concentration is lower
  than that inside a cell and the water
  concentration is greater outside the cell

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• water will move into the cell if it is placed in
  a hypotonic solution think hippo fat
• a fat cell - cell will swell in hypotonic
  solution

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In distilled (pure) water

• There are more water molecules outside the plant
  cells, so water will move into the plant cells,
  making the plant more firm

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How Cells Deal with Osmosis

• When in a hypotonic solution, some cells will
  pump out solutes so that water is less likely to
  move into the cell

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Isotonic solution

• a solution whose solute concentration and water
  concentration equals that inside a cell

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Facilitated diffusion -

• diffusion of materials across a cell membrane
  assisted by carrier molecules (proteins)

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Active Transport

• Energy-requiring process that moves material
  across a cell membrane against a concentration
  difference

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Contractile vacuole

• structure in unicellular organisms that removes
  excess water by contracting requires the cell to
  use energy

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Organization

• 1. Cell basic unit of structure and function
  of organisms
• Ex epithelial cell, red blood cell, smooth
  muscle cell

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• 2. Tissue group of similar cells that work
  together to carry out a specific job
• Ex bone, blood, skeletal muscle

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• 3. Organ Group of tissues that work together
  to do a certain job
• Ex heart, stomach, ovaries

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• 4. Organ System group of organs that work
  together to do a certain job
• Ex digestive system, circulatory system,
  reproductive system