Download Cell Overview – History and Structure

Cell Overview – History and Structure
“A View of the Cell”
Cytology: the study of cells
Histologist: studies cells
Organization
- Atom
- Molecule
- __________________
- __________________
- Tissue
- Organs
- Systems
- Organisms
Important Figures in the Discovery of Cells
1. Anton van Leeuwenhoek (leave-in-hook)
* Mid-1600s - Holland
* Used hand lens microscope to observe pond water
* Observed microscopic life
2. Robert Hooke
* Mid-1600s - England
* Used microscope to observe living tissues
* Named chambers “_________”
3. German Cell Biologists
a. Matthias Schleiden
- Concluded that all
_______ are made
up of cells.
b. Theodor Schwann
- Concluded that all _____________ are made up of cells.
4. Rudolph Virchow
* 1855 - Germany
* New cells can only be produced from ____________ cells,
confirmed by French scientist Louis Pasteur.
5. Watson and Crick
* 1953 Watson & Crick proposed that ______ is composed of two strands of nucleotides
held together by nitrogenous bases in the form of a _______________ __________.
Cell Theory
1) All organisms are composed of one or more __________
2) The cell is the basic unit of structure and functions of living things
3) All cells come from ________________ cells
To Be a Cell
- __________________: cell membrane, made of
2 layers of phospholipids
- __________________: carbohydrate and
water based solution that suspends all internal
parts of the cell
- __________________: produces proteins
- _______: genetic material made of nucleic acids
Two Types of Cells
1. Prokaryote: bacteria, archaebacteria
2. Eukaryote: protist, fungus, plant, animal
Prokaryote
- No nucleus
- No organelles
- Small
- Simple
- Plasma membrane, ribosome, cytoplasm, DNA
- Typically unicellular
- Ex. Archaebacteria
Eukaryote
- complex
- contains 4 basic components plus
organells.
- multi-cellular organisms
- many variations
- organelles: small
compartments that carry out
specialized functions within a cell.
Plasma Membrane
- A flexible boundary between the cell and its environment maintains a balance of
nutrients, etc
- Selective permeability
- A process in which a membrane allows some molecules to pass through while keeping
others out
Structure of Plasma Membrane
A. Phospholipids
o A double layer that creates water-soluble
outsides surrounding water insoluble insides
B. Transport Proteins
o Span the entire membrane to regulate which
molecules enter and which leave
Major Organells
- Nucleus – both plant and animal
- Chloroplast - plants
- Mitochondria – plant and animal
- Centrioles - animal
**Don’t forget the importance of
the plasma membrane!
- Organelles are membrane bound
structures with particular (specialized)
functions within eukaryote cells.
1. Nucleus = cell control!
- Chromatin
- Strands of genetic material (____) that contains the directions for making proteins.
Forms chromosomes
- Nucleolus, Nuclear Pores, and Nuclear Envelope
- A prominent body within the nucleus, which makes the ribosomes
2. Chloroplast
- Containing the green pigment, chlorophyll, these oval bodies capture light _________ and
turn it into chemical __________ (____________________).
3. Mitochondria
- Rod-shaped organelle with many inner folds, which breaks down sugar to release its stored
_______________ for cell use (______ ______________)
4. Centrioles
- Pairs of microtubles
that plays an important
role in cell division.
Plant and Animal Cell Similarities
- Cell membrane that surrounds the cell
- Cytoplasm
- Nucleus that houses DNA
- Ribosomes for protein production
- Mitochondria that breaks down food and creates energy for the cell.
- Vacuoles for storage of food, water, and waste. Although plants have one large vacuoles
compared to animals many small vacuoles.
Plant and Animal Cell Differences
- Plants contain a cell wall that surrounds the cell membrane and provides shape and support.
- Plants contain chloroplasts for photosynthesis
- Plant cells have a brick-like shape where as animal cells are more cylindrical.
- Plants use chloroplasts to store energy in sugar; animal cells use mitochondria to release
energy stored in food. Plants contain a cell wall that surrounds the cell membrane and
provides shape and support.
- Plants contain chloroplasts for photosynthesis
- Plant cells have a brick-like shape where as animal cells are more cylindrical.
- Plants use chloroplasts to store energy in sugar; animal cells use mitochondria to release
energy stored in food.
Endosymbiotic Theory
Scientific explanation:
- Origin of mitochondria and chloroplasts
 Endosymbiotic bacteria – bacteria that live within other cells and perform specific
functions for host cells
 Endosymbiotic Theory – suggests critical stage in evolution of eukaryotic cells involved
endosymbiotic relationships with prokaryotes
 Energy-producing bacteria reside in larger bacteria, eventually evolving into
mitochondria
 Photosynthetic bacteria live within larger bacteria, leading to evolution of
chloroplasts
Support for endosymbiotic theory
- Presence of numerous symbiotic relationships
- Present-day mitochondria, chloroplasts, and centrioles contain their own DNA
 Similar to DNA of bacteria in size and character