Cell Structure and Function. Scientists responsible for the tools and foundations of cell biology:. Robert Hooke 1665 term “cell” observed cork. Scientists responsible for the tools and foundations of cell biology:. Anton van Leeuwenhoek 1674
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Cell Structure and Function
Anton van Leeuwenhoek
used high quality lenses to improve microscope
pond water - animalcules
recognized cells as basic unit of life
discovered the cell’s nucleus
nucleus directs cell division
plants composed of cells
animals composed of cells
new cells arise from the division of preexisting cells
The work of these scientists provided information significant to the development of the cell theory
All living organisms are alike because they are composed of cells
… by studying the composition and chemistry of the cell, we understand the chemistry and composition of all kinds of life forms
The study of matter and the changes in matter
Pertaining to life
Polymer: Very large molecule made from individual pieces
Hydrogen and Carbon
3. How could the canning process change bromelin?
4. What could you do to fresh pineapple that would allow the salad to gel?
A. Enzymes put molecules together……SYNTHESIS.
B. Enzymes take molecules apart…… DIGESTION.
C. Enzymes control chemical reactions…….LIFE.
D. Enzymes make chemical reactions require less energy.
Lock and Key Theory for Enzyme Action
Quick Quiz!! If you found a new organism and it was multicellular, did not contain chloroplasts, but did have cell walls, which kingdom would you expect it to belong to?
Oparin – Haldane Hypothesis (1920’s)
Idea based on the behavior of energy and molecules found in all living things
Hydrogen gas (H2)
Ammonia gas (NH3)
Water vapor (H2O)
Very Little Oxygen!!
UV radiation synthesized the first organic compounds from inorganic precursors
Stanley Miller (1953)
Set up experiments using O-H hypothesis
Produced simple amino acids
- building blocks for all life forms, protein components
Molecules + Energy = Larger molecules and chemical compounds
20 amino acids
DNA and RNA
These have all been recreated in the laboratory. All the steps to making simple cells have been recreated under lab conditions!!
1.) The Earth consisted of prebiotic soup from which
small organic compounds were made
2.) Small molecules were joined to make larger molecules
3.) Molecules organized into droplets with different
Characteristics than the molecules alone.
4.) Origin of heredity: formation of DNA allows primitive
cells to reproduce themselves and pass on info.
Lynn Margulis (1970) proposed an evolutionary explanation for eukaryotic cells
…Eukaryotic cell is the result of prokaryotic cells living enclosed in one cell
mutually benefiting from the relationship
Complex and organized
complex and specialized functions
Ex. – all body cells, plant cells, fungi, etc.
Evolutionarily advanced over prokaryotic cells
Ex. – Bacteria
Precursors to eukaryotes
-Separates the cell from its surroundings
-Protects the cell contents
- Determines what raw materials will enter*
- Releases waste products produced inside of cell*
…flexible barrier allowing only lipid soluble substances
into the cell
…fluid mosaic model = individual phospholipids can move around within the membrane
…pump for specific substances into/out of cells
…open channels for certain materials
…membrane stabilizers (cholesterol)
…chemical identification of the cell
- control center, cell activities are primarily directed from the nucleus
- Contains the DNA and proteins = CHROMATIN
- Chromatin condenses during reproduction to form CHROMOSOMES
Dark staining structure within the nucleus
Contains r-RNA, makes ribosomes
Plasm = fluid
Cyto = cell
Inside of the nucleus
Outside of the nucleus
Organelles in the cytoplasm of all eukaryotic cells:
Organelles in some eukaryotic cells:
Tiny structure where proteins are assembled from amino acids
Network of membranes dividing cytoplasm and directing the flow of material through the cell
Rough – ribosomes attached, rough appearance
Smooth – no ribosomes, smooth appearance
Tightly grouped membranous structure where proteins are condensed, collected, and packaged for storage or shipment out of the cell
Produces lysosomes, vesicles, and vacuoles
Lysosome: sac-like structure containing enzymes for cellular breakdown; recycling plant
Vacuoles and Vesicles:
- store carbs, water, salts, fats, etc.
-Vacuoles may be larger
-In plants, vacuole provides support
- Vacuoles stay in cells
- Vesicles bring things into/out of cells
Microtubule and microfilament network that provides a framework
Movement of proteins inside cell
Movement of the cell
Contain their own DNA
Takes chemical fuel (glucose) and converts it into small useable packages (ATP)
Contain their own DNA
Light absorbing structure that package ENERGY in glucose
Structure that surrounds cell membrane
Provides support and rigidity to cells
In plants, composed of cellulose
In fungi, composed of chiten
Tail-like structures used for locomotion
Short, hair-like structures on the surface of the cell
Used for locomotion and to move materials near cell
Only in animal cells
Used in cell division