Biology 1- Chapter 7 Notes Prentice Hall (pg. 168-193)

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Biology 1- Chapter 7 NotesPrentice Hall (pg.
168-193)

• 71 Life Is Cellular
• A. The Discovery of the Cell
• 1. Early Microscopes
• 2. The Cell Theory
• B. Exploring the Cell
• C. Prokaryotes and Eukaryotes
• 1. Prokaryotes
• Eukaryotes
• 72 Eukaryotic Cell Structure
• A. Comparing the Cell to a Factory
• B. Nucleus
• C. Ribosomes
• D. Endoplasmic Reticulum
• E. Golgi Apparatus
• F. Lysosomes
• G. Vacuoles
• H. Mitochondria and Chloroplasts
• 1. Mitochondria

• 73 Cell Boundaries
• A. Cell Membrane
• B. Cell Walls
• C. Diffusion Through Cell Boundaries
• 1. Measuring Concentration
• 2. Diffusion
• D. Osmosis
• 1. How Osmosis Works
• 2. Osmotic Pressure
• E. Facilitated Diffusion
• F. Active Transport
• 1. Molecular Transport
• 2. Endocytosis and Exocytosis
• 74 The Diversity of Cellular Life
• A. Unicellular Organisms
• B. Multicellular Organisms
• 1. Specialized Animal Cells
• 2. Specialized Plant Cells

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7.1 The History of the Cell Theory

• Before microscopes were invented, people believed
  that diseases were caused by curses and
  supernatural spirits.
• As scientists began using microscopes, they
  quickly realized they were entering a new
  worldone of microorganisms.
• Microscopes enabled scientists to view and study
  cells, the basic units of living organisms.

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Development of Light Microscopes

• The first person to record looking at water under
  a microscope was Anton van Leeuwenhoek.
• The microscope van Leeuwenhoek used is considered
  a simple light microscope because it contained
  one lens and used natural light to view objects.
• Compound light microscopes use a series of lenses
  to magnify objects in steps.

• These microscopes can magnify objects up to 1500
  times.

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The Cell Theory

• Robert Hooke was an English scientist who lived
  at the same time as van Leeuwenhoek.
• Hooke used a compound light microscope to study
  cork, the dead cells of oak bark.
• He thought the structures he observed resembled
  the one room cells
• Hooke is credited with giving cells their name
• Cells are the basic building blocks of all living
  things.

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The cell theory is made up of three main ideas

• 1. All organisms are composed of one or more
  cells.
• 2. The cell is the basic unit of structure and
  function of organisms.
• 3. All cells come from preexisting cells.
• Three Scientists contributed to the Cell Theory
• 1838- Schleiden plants are made of cells
• 1839- Schwann animals are made of cells
• 1855- Virchow New cells are produced from the
  division of old cells

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Development of Electron Microscopes

• The electron microscope was invented in the
  1940s.
• This microscope uses a beam of electrons to
  magnify structures up to 500,000 times their
  actual size.

• There are two basic types of electron
  microscopes.
• The scanning electron microscope scans the
  surface of cells to learn their three dimensional
  shape.
• The transmission electron microscope allows
  scientists to study the structures contained
  within a cell.

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Scanning Probe Microscope

• Discovered in the 1990s
• Produces images by tracing the surfaces of
  samples with a fine probe
• Can observe single atoms in the air or in solution

SEM Picture of Neuron
Condensed DNA by Scanning probe
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Two Basic Cell Types
Prokaryotic and Eukaryotic Cells
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Prokaryotic Cells

• Cells that do not contain internal membrane-bound
  structures and do not have a nucleus are called
  prokaryotic cells.

• Unicellular organisms such as bacteria are very
  simple.
• They still carry out all of lifes activities
  such as respiration, cell reproduction, growth,
  etc.

Prokaryotic Cell
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Eukaryotic Cells

• Cells containing membrane-bound structures and a
  nucleus are called eukaryotic cells.

• Most of the multi-cellular plants and animals
  are made up of cells that are very specialized
  and diverse in their structures and functions

Eukaryotic Cell
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7.2 Eukaryotic Cell Structure

• Organelles
• The membrane-bound structures within eukaryotic
  cells are called organelles.
• Each little organ has a specific function that
  contributes to cell survival.
• Separation of organelles into distinct
  compartments benefits the eukaryotic cells.
• Lysosomes
• Nucleus
• Plasma Membrane
• Endoplasmic Reticulum
• Mitochondrion

• Biologists divide the cell into
• two major parts
• The nucleus is the central membrane-bound
  organelle that manages cellular functions.
• Everything between the cell membrane and the
  nucleus is called the cytoplasm.

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Nucleus

• Nuclear envelope double layered membrane
  surrounding nucleus contains small pores
• Nuclear pores- allow transport of materials in
  and out of nucleus
• Chromatin-granular material visible within the
  nucleus consists of DNA tightly coiled around
  proteins

Nucleolus

• Chromosomes threadlike structure within the
  nucleus containing the genetic information that
  is passed from one generation of cells to the
  next (chromosomes are formed when chromatin
  condenses during cell division)
• Nucleolus dense material in nucleus makes
  ribosomes which make proteins

Chromatin
Nuclear Envelope
Nuclear Pore
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Ribosomes

• Ribosomes are made in the nucleolus.
• They travel in and out of the nucleus through the
  nuclear pores.

• Ribosomes are small particles within the cell on
  which proteins are assembled made of RNA and
  protein
• They can be free (in the cytoplasm)
• They are also attached to the rough endoplasm
  reticulum

Ribosomes
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Endoplasmic reticulum

• The endoplasmic reticulum (ER) is responsible for
  assembly, transport, and storage of molecules
  within cell.
• There are two types

• Rough ER- contains ribosomes and makes proteins
• Smooth ER- lacks ribosomes has enzymes that make
  membrane lipids and detoxifies drugs
• Liver cells contain many smooth ER for
  detoxification

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Golgi Apparatus

• Stacks of membranes in the cell that modifies,
  sorts, and packages proteins from the endoplasmic
  reticulum

• The Golgi apparatus is like a customization shop
  where finishing touches are added to proteins.

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Lysosomes

• Lysosomes are organelles that contain digestive
  enzymes. They digest excess or worn out
  organelles, food particles, and engulfed viruses
  or bacteria.
• The lysosomes are the clean-up crew of the cell
• Tay-Sachs disease is caused by excess lipid
  accumulation on the brain. The cause of this
  disease has been traced to lysosomes that failed
  to function properly

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Vacuoles

• Vacuoles are membrane-bound spaces used for
  temporary storage of materials (such as water,
  salts, proteins, and carbohydrates)
• Notice the difference between vacuoles in plant
  and animal cells.

Plant Cell
Vacuole
Animal Cell
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• Paramecium have a contractile vacuole that pumps
  excess water out of the cell, which aids with
  homeostasis

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Mitochondria

• Mitochondria are membrane-bound organelles in
  plant and animal cells that transform energy for
  the cell.
• A mitochondria, like the endoplasmic reticulum,
  has a highly folded inner membrane.
• The folds increase the surface area of the
  mitochondrion in order to make more energy (ATP)
• Cellular Respiration takes place in the
  mitochondria of cells

• Cellular respiration is the process that converts
  chemical energy stored in food into ATP energy
  for cells to use.
• Muscles cells (needed for movement) contain a
  large number of mitochondria for energy
  production

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Chloroplasts

• Chloroplasts are found in cells of plants and
  some other organisms
• Chloroplasts are organelles that capture light
  energy and produce food to store for a later
  time.
• Photosynthesis takes place in the chloroplasts
• Chloroplasts contain green pigment called
  chlorophyll.

• Chlorophyll traps light energy and gives leaves
  and stems their green color.
• Chloroplasts acts like a solar power plant

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Organelle DNA

• Lynn Margulis - described mitochondria and
  chloroplasts as free-living aerobic prokaryotes
  which developed a partnership with host cell
  endosymbiosis hypothesis
• chloroplasts and mitochondria have their own
  circular DNA ribosomes, make their own
  proteins, reproduce on their own

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Cytoskeleton

• Cells have a support structure called the
  cytoskeleton within the cytoplasm.
• It is a network of proteins that help maintain
  cellular shape and movement
• The cytoskeleton is composed of microtubules and
  microfilaments.

• Microtubules are thin, hollow cylinders made of
  protein that maintain cell shape
• Microfilaments are thin solid protein fibers that
  help cells move (amoeba)

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Centrioles

• Made of microtubules and cytoskeleton
• one of two tiny structures located in the
  cytoplasm of animal cells near the nuclear
  envelope
• help to organize cell division (helps cells split
  into two)
• only found in animal cells

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Cilia and Flagella
Cilia

• Some cell surfaces have cilia and flagella, which
  are structures aid in locomotion or feeding.
• Made of microtubules from the cytoskeleton
• Cilia and flagella can be distinguished by their
  structure and by the nature of their action.
• Cilia are short, numerous, hair-like projections
  that move in a wavelike motion.
• Flagella are long projections that move in a
  whip-like motion.
• Flagella and cilia are the major means of
  locomotion in unicellular organisms.

Flagella
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Microscope Lab

• Purpose To compare the basic structures and
  shape of plant and animals cells by looking at
  onion (epidermal) cells and cheek (epithelial)
  cells
• epidermal cells- cells that make up the
  protective outer covering of plants tissue that
  covers the human body
• epithelial cells- cells that make up tissues that
  cover bodies or organs
• To review basic microscope parts and lab
  techniques like staining cells and preparing a
  wet mount for microscope slides

• Plant Cells Animal Cells
• Shape Rectangular Circular
• Components Cell wall Cell Membrane
• Cell Membrane Nucleus
• Nucleus

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Plant cells have structures not found in animal
cells

• Cell wall - help give plants shape, support and
  protection
• Chloroplast-site of photosynthesis

• Large central vacuole - contains water which
  helps keep plant from wilting when the vacuole
  is full it presses against the cell wall to give
  the plants rigidity (turgid pressure)

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Animal cells have structures not found in plant
cells

• Cytoskeleton- animal cells use the cytoskeleton
  to help with support and aid in movement

• Centrioles-aid in cell division

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Differences between Plant/Animal Cells
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Animal Cell
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Plant Cell
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7.3 Cellular Boundaries

• The cell membrane acts as a semi-permeable
  membrane.

• The cell wall is a fairly rigid structure located
  outside the plasma membrane that provides
  additional support and protection.
• It is present in plants, algae, fungi, and many
  prokaryotes.
• Allows water oxygen, carbon dioxide to pass
  through easily
• Plant cell walls are made of cellulose (fiber)

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Cell Membrane

• All cells are surrounded by the cell membrane
• It regulates what enters and leaves the cell and
  provides protection and support
• It protects against viral and bacterial invaders
• It consists of two layers called the lipid
  bilayer.
• The cell membrane is also called the plasma
  membrane

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The Structure of the Cell Membrane

• Lipids (lipid bilayer)
• Proteins embedded in bilayer
• Some proteins form channels or pumps to move
  material across the membrane
• Carbohydrates attached to proteins
• These act as signals or identification cards,
  allowing the cells to recognize each other
• Because it allows different components to move
  through it, it is also called the fluid mosaic
  model

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The Plasma Membrane

• All living cells must maintain a balance
  regardless of internal and external conditions.
  Survival depends on the cells ability to
  maintain the proper conditions within itself.
• Why cells must control materials
• The plasma membrane is the boundary between the
  cell and its environment.

• It is the plasma membranes job to
• allow a steady supply of glucose, amino acids,
  and lipids to come into the cell no matter what
  the external conditions are.
• remove excess amounts of these nutrients when
  levels get so high that they are harmful.
• allow waste and other products to leave the cell.

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Cell membrane

• This process of maintaining the cells
  environment is called homeostasis.
• Semi- (selectively) permeability is a process
  used to maintain homeostasis in which the plasma
  membrane allows some molecules into the cell
  while keeping others out.

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Diffusion

• The process by which molecules tend to move from
  an area where they are more concentrated to an
  area where they are less concentrated.
• Molecules move through cell boundaries
• Concentration- the amount of solute in a given
  amount of solution
• Equilibrium- when the concentration of a solute
  is the same throughout the solution
• Does not require energy moves down the
  concentration gradient (H?L)
• Moves oxygen, carbon dioxide and water

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Osmosis

• diffusion of water through a selectively
  permeable membrane

Water will keep moving until equilibrium is
reached
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Hypertonic Solution

• concentration of solutes in solution is higher
  than the concentration of solutes inside the cell
• causes water to diffuse out of the cell may
  cause cell to shrivel and shrink disrupts
  metabolism and may kill cell

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Hypotonic Solution

• concentration of solutes is lower than the
  concentration inside the cell
• causes water to diffuse into the cell
• animal cells may burst in a hypotonic solution
• plant (and many bacteria) cells do not burst
  because they are surrounded by a rigid cell wall

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Isotonic Solution

• the concentration of solutes equals the
  concentration of solutes inside the cell
• does not result in the net diffusion of water
  into or out of the cell
• kidneys and skin help to maintain isotonic
  conditions in your body

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The Effects of Osmosis on Cells
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Facilitated Diffusion

• movement of specific molecules across cell
  membranes through protein channels
• passive - does not require an input of energy
• always moves particles down a concentration
  gradient (H?L)
• because these molecules re polar they must travel
  through channels in transport proteinsex glucose

Glucose molecules
High Concentration
Cell Membrane
Protein channel
Low Concentration
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Active Transport

• energy-requiring process that moves material
  across a cell membrane against a concentration
  difference
• requires energy from ATP molecules
• can move particles up a concentration gradient
  (from low to high)
• requires carrier proteins to pump particles
  across membrane
• ex Na-K pumps in nerve cells, movement of
  nutrients into plant roots

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Bulk transport - large molecules, food, and other
substances are packaged in membrane-bound sacs
and moved across the membrane

• The graph to the right shows the relative size of
  molecules that move in and out of the cell
• Requires energy
• Endocytosis
• Phagocytosis
• Pinocytosis
• Excoytosis

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Endocytosis

• process by which a cell takes material into the
  cell by infolding of the cell membrane
• Two Types
• Phagocytosis (cell eating)-process in which
  extensions of cytoplasm surround and engulf large
  particles and take them into the cell  
• Pinocytosis (cell drinking)-process by which a
  cell takes in a liquid from the surrounding
  environment

Amoeba ingesting food
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Exocytosis

• wastes and cell products leave the cell by fusing
  with membrane
• products packaged by Golgi apparatus and excreted
  from cell
• Removal of water by the contractile vacuole of
  paramecium.

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7.4- Diversity of Cellular Life

• Unicellular Organisms
• Sometimes single cells are the organism
• Grow, respond to the environment, transform
  energy, and reproduce

• Multicellular Organisms
• Made up of many cells
• Very diverse
• Depend on communication and cooperation between
  specialized cells
• Cell specialization
• Cells throughout an organism can develop in
  different ways to perform different tasks

Yeast Volvox Bacterium
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Cell Specialization

• Animal cells
• Red Blood Cells- carries oxygen small and round
  to fit through vessels
• Pancreatic Cells- produce enzymes to break down
  food contains many ribosomes and rough ER to aid
  in this process
• Muscle Cells- long and threadlike to aid in
  movement contain many mitochondria for energy
  production
• Plant Cells
• Guard cells- in the pores of leaves aids in
  water exchange

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Cell Shape is Related to Function
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Levels of Organization
Muscle cell
Smooth muscle tissue
Stomach
Digestive system

• Many multicellular organisms have structures
  called organs that have a specific function and
  work with other organs.
• Working together, these organs carry out the life
  processes of the entire organism.
• Multicellular organisms contains cells, tissues,
  organs and organ systems