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The Cell

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Standard 5: Identify cells, tissues, organs, organ systems, organisms, populations, communities, and ecosystems as levels or organization in the biosphere.

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Standard 4: Describe similarities and differences of cell organelles, using diagrams and tables.

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Standard 2: Describe the cell process necessary for achieving homeostasis, including active and passive transport, osmosis, diffusion, exocytosis, and endocytosis.

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Introduction to the Cell

  • You have been taught that Biology is the study of life or that which was once living. So how does life actually begin? It begins with molecules. Those molecules are going to form tiny structures called cells.

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Introduction to the Cell

  • The cell is the smallest unit of life. It is the basic structure and function of living things.
  • The living parts of the universe starts off as tiny cells and grows to form our biosphere.

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The Cell

The cell is the basic building block of life. It it responsible for the many levels of organization that we come in contact with. It is organized as follows:

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Molecules🡪Cells🡪Tissues🡪Organs🡪Organ Systems>

Organisms>Populations>Communities>Ecosystems🡪Bisosphere

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This means that molecules make up cells. Cells make up tissues. Tissues make up organs and organ make up organ systems. Organ systems are going to make up organisms. Organisms will make up populations. Populations will make up communities and the communities will make up the ecosystems. The ecosystems will make up the biospehere.

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The Cell Discovery and Theory

  • There are several scientist that are noted as making contributions to either the discovery of the cell or to making of the cell theory.

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The Cell Discovery and Theory

Notable Scientists

  • Robert Hooke- first viewed the cell under a microscope that he built using a piece of cork.
  • Anton van Leeuwenhoek-microscope maker and was first to view living cells under the microscope.
  • Matthias Schleiden-studied plant cells.
  • Theodore Schwann-studied animal cells.
  • Rudolph Virchow-studied how diseases affected cells.

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Cell Theory

The cell theory states that:

  • All living things are made of one or more cells.
  • The cell is the basic unit of structure and function in living organisms.
  • All cells arise from pre-existing cells.

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Two Type of Cells

  • Prokaryotes- organism that does not contain a nucleus or membrane bound organelles. Ex. Bacteria (Monera Kingdom)
  • Eukaryotes- organisms that contain a membrane bound nucleus and organelles. Ex. plant and animal cells

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Eukaryotes

There are 4 types of eukaryotes.

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  • Plant Cells
  • Animal Cells
  • Protist Cells
  • Fungal Cells

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Plant Cells

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Animal Cells

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Cell Organelles

  • Cytoplasm-the liquid inside the cell
  • Cell/Plasma membrane-made of lipids and proteins, it is the boundary of the cell and control what enters and leaves the cell.
  • Nucleus-control center of the cell where the genetic material is found

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Cell Organelles

  • Cell wall-surrounds the plant cell and is made of cellulose
  • *Ribosomes-very small organelles that are the sites of protein synthesis.
  • Endoplasmic reticulum- system of tubes in the cytoplasm involved in transporting materials

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Cell Organelles

  • Golgi Apparatus (Golgi Body or Golgi Complex)-involved in packaging and distribution
  • *Mitochondria-site of cellular respiration and is the powerhouse of the cell (where ATP is made)

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Cell Organelles

  • Lysosomes-stores digestive enzymes
  • *Chloroplast-site of photosynthesis (where chlorophyll is made)
  • Vacuole-involved in food storage

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Cell Organelles

The plant and animal cells share the same organelles except that plant cells have a cell wall, chloroplasts, and central (large) vacuole.

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Cell Locomotion

  • Cells can either use cilia or flagella to aid in locomotion (movement)
    • Cilia- short hair-like particles found on some cells to help aid in movement and food gathering ex. on the paramecium
    • Flagella – long whip-like projections that aids in movement

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Cilia and Flagella

Cilia

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Cell Survival

  • In order for cells to survive, they must take in nutrients and get rid of waste products, the cells move these substances in and out by either active or passive transport.

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Active Transport

  • Active Transport: the cell requires energy to move substances across the cell membrane in the opposite direction of concentration. It is not spontaneous. Active transport moves substances from an area of low concentration to an area of high concentration.

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Active Transport

2 Types of Active Transport

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      • Endocytosis-a form of active transport in which a cell moves substances into the cell.
      • Exocytosis- a form of active transport in which a cell moves substances out of the cell.

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Active Transport

  • Endocytosis Exocytosis

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Passive Transport

  • Passive Transport-transport that is spontaneous and does not require energy. Molecules move through the plasma/cell membrane from an area of high concentration to an area of low concentration.

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2 Types of Passive Transport

      • Diffusion- the process by which substances move from an area high concentration to an area of low concentration.

Facilitated diffusion-occurs when carrier proteins in the plasma membrane assist in the passage of materials into or out of the cell.

      • Osmosis- the movement of water through a semi-permeable membrane from an area of high concentration to an area of low concentration.

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Osmosis

  • There are 3 types of osmotic solutions
      • Isotonic Solutions-has equal concentration of substances both inside the cell and outside. The cell will not gain or lose water.
      • Hypotonic Solutions-causes the cell to swell, moves water into the cell.
      • Hypertonic Solutions--causes the cell to shrink, moves water out of the cell.

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Isotonic Solutions

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If the concentration of solute (salt) is equal on both sides, the water will move back and forth but it won't have any result on the overall amount of water on either side.

"ISO" means the same

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Hypotonic Solutions

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The word "HYPO" means less, in this case there are less solute (salt) molecules outside the cell, since salt sucks, water will move into the cell.

The cell will gain water and grow larger. In plant cells, the central vacuoles will fill and the plant becomes stiff and rigid, the cell wall keeps the plant from bursting

In animal cells, the cell may be in danger of bursting, organelles called CONTRACTILE VACUOLES will pump water out of the cell to prevent this.

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Hypertonic Solutions

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The word "HYPER" means more, in this case there are more solute (salt) molecules outside the cell, which causes the water to be sucked in that direction.

In plant cells, the central vacuole loses water and the cells shrink, causing wilting.

In animal cells, the cells also shrink.

In both cases, the cell may die.

This is why it is dangerous to drink sea water - its a myth that drinking sea water will cause you to go insane, but people marooned at sea will speed up dehydration (and death) by drinking sea water.

This is also why "salting fields" was a common tactic during war, it would kill the crops in the field, thus causing food shortages.

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Cell Division, Mitosis, & Meiosis

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Reproduction In Cells

Cells can reproduce either by sexual or asexual reproduction.

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    • Sexual Reproduction- reproduction using a sperm and an egg cell.

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    • Asexual Reproduction- reproduction in which and organism produces another organism identical to itself or without the use of a sperm and egg cell.

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Cell Division (Reproduction)

There are two types of cell division: Mitosis and Meiosis

    • Mitosis- a type or reproduction in which the cell divides and produces 2 daughter cells that are identical to the parent cell. (asexual reproduction)

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    • Meiosis- a type of cell division in which the parent cell will divide twice and produce 4 gametes (sex cells) (sexual reproduction)

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Meiosis and Mitosis

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Stages of Mitosis

Interphase

Prophase

Metaphase

Anaphase

Telophase & Cytokinesis

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Animated Mitosis Cycle

http://www.cellsalive.com/mitosis.htm

  • Interphase
  • Prophase
  • Metaphase
  • Anaphase
  • Telophase & Cytokinesis

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Interphase �occurs before mitosis begins

  • Chromosomes are copied (# doubles)
  • Chromosomes appear as threadlike coils (chromatin) at the start, but each chromosome and its copy(sister chromosome) change to sister chromatids at end of this phase

CELL MEMBRANE

Nucleus

Cytoplasm

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Interphase

Animal Cell

Plant Cell

Photographs from: http://www.bioweb.uncc.edu/biol1110/Stages.htm

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Prophase �1st step in Mitosis

  • Mitosis begins (cell begins to divide)
  • Centrioles (or poles) appear and begin to move to opposite end of the cell.
  • Spindle fibers form between the poles.

Centrioles

Sister chromatids

Spindle fibers

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Prophase

Animal Cell

Plant Cell

Photographs from: http://www.bioweb.uncc.edu/biol1110/Stages.htm

Spindle fibers

Centrioles

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Metaphase � 2nd step in Mitosis

  • Chromatids (or pairs of chromosomes) attach to the spindle fibers.

Centrioles

Spindle fibers

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Metaphase

Animal Cell

Plant Cell

Photographs from: http://www.bioweb.uncc.edu/biol1110/Stages.htm

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Anaphase �3rd step in Mitosis

  • Chromatids (or pairs of chromosomes) separate and begin to move to opposite ends of the cell.

Centrioles

Spindle fibers

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Anaphase

Animal Cell

Plant Cell

Photographs from: http://www.bioweb.uncc.edu/biol1110/Stages.htm

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Telophase �4th step in Mitosis

  • Two new nuclei form.
  • Chromosomes appear as chromatin (threads rather than rods).
  • Mitosis ends.

Nuclei

Nuclei

Chromatin

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Telophase

Animal Cell

Plant Cell

Photographs from: http://www.bioweb.uncc.edu/biol1110/Stages.htm

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Cytokinesis�occurs after mitosis�

  • Cell membrane moves inward to create two daughter cells – each with its own nucleus with identical chromosomes.

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Animal Mitosis -- Review

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Interphase�                                                             

Prophase�                                                             

Metaphase�                                                             

Anaphase�                                                             

Telophase�                                                             

Interphase�                                                             

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Plant Mitosis -- Review

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Interphase�                                                             

Prophase�                                                             

Metaphase�                                                             

Anaphase�                                                             

Telophase�                                                             

Interphase�                                                             

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REMEMBER!

  • Interphase
  • Prophase
  • Metaphase
  • Anaphase
  • Telophase
  • Cytokinesis

IPMATC

I Pray More At The Church

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Cell Cycle

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The Cell Cycle

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- Cell Division

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Asexual Reproduction

Mitosis is asexual reproduction. Asexual reproduction is reproduction without the use of a sperm and an egg cell.

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How do little elephants grow up to be BIG elephants?

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Why do animals shed their skin?

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How does skin repair itself?

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The process of asexual reproduction begins after a sperm fertilizes an egg.

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Three reasons why cells reproduce by asexual reproduction:�� 1. Growth� 2. Repair� 3. Replacement

Skin cancer - the abnormal growth of skin cells - most often develops on skin exposed to the sun.

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Cells that reproduce by asexual reproduction reproduce constantly.

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Forms of Asexual Reproduction

  • 4 Types of Asexual Reproduction
    • Fission- asexual reproduction in which a organism splits into two equal parts.
    • Budding- asexual reproduction in which an organism can grow another organism from the top, bottom, or sides of the organisms body.

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Forms of Asexual Reproduction

    • Regeneration- asexual reproduction in which an organism can re-grow missing body parts
    • Fragmentation- asexual reproduction in which an organism can be broken or cut up and those parts will grow into a totally new but identical organism.

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Stages of Meiosis

  • Interphase Metaphase II
  • Prophase Anaphase II
  • Metaphase Telophase II
  • Anaphase
  • Telophase
  • Interkenesis
  • Prophase II

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Diploid and Haploid Cells

  • Haploid- having a single set or (n) number of chromosomes
  • Diploid- having two sets or two times the (n) number of chromosomes

EX. Humans have 23 pair of chromosomes or 46 total (diploid) chromosomes. n=23 (haploid)

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Sex Cells

Sex Cells are also referred to as gametes.

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  • Sperm cells and egg cells are called gametes and contains one set of chromosomes “n or haploid”.
  • Once the sperm fertilizes the egg it becomes a zygote (somatic cell) with double the number of chromosomes (diploid).

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Crossing Over - variation

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Sex Chromosomes

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XX chromosome – female

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XY chromosome - male

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Meiosis

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  • Meiosis is sexual reproduction.
  • The purpose of meiosis is to produce gametes (4) in preparation for reproduction. (These gametes may sometimes referred to as the daughter cells of Meiosis.)
  • Meiosis causes variation which means that no organism produced during meiosis will be identical.

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Meiosis Animation

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