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Prokaryotic Cell
Cellular Structure and Function
They do not contain membrane-bound organelles
Cell Discovery and Theory
Steven P. Lynch
Section 1
Prokaryotes are single-celled organisms that lack a nucleus and other internal compartments
Prokaryotic Cell Prokaryotic cells includes all bacteria Prokaryotes contain only the following
structures:
1. Cell wall (peptidoglycan)2. Plasma membrane3. Genetic material as a single circular molecule of
DNA4. Ribosomes5. Cytoplasm6. Plasmid (Small circular piece of DNA that only
some bacteria possess)
Cellular Structure and FunctionSection 1
Prokaryotic Cell
Cellular Structure and Function
Cell Discovery and Theory
Section 1
Eukaryotic Cell More complex structure than prokaryotes
Cellular Structure and Function
In addition to the prokaryotic structures, eukaryotes also have membrane bound organelles, including a nucleus
Section 1
Cellular Structure and Function
Cell Discovery and Theory
Section 1
Comparing Prokaryotic and Eukaryotic Cells
Cellular Structure and Function
Cell Discovery and Theory
The
Section 1
Plasma Membrane Thin, flexible boundary between the cell
and its environment
The Plasma Membrane
Cellular Structure and Function
Allows nutrients into the cell Allows waste to leave the cell
Section 1
Selective Permeability
Cellular Structure and Function
The plasma membrane controls the movement of substances into and out of the cell.
The plasma membrane is selectively permeable, meaning it chooses what enters and leaves the cell
The Plasma Membrane
Section 2
The plasma membrane is composed of the phospholipid bilayer.
Cellular Structure and Function
A phospholipid molecule is composed of a glycerol backbone, two fatty acid chains, and a phosphate group.
The Plasma Membrane
Section 2
Cellular Structure and Function
The Plasma Membrane
Section 2
Fluid Mosaic Model
Cellular Structure and Function
The phospholipid bilayer allows other molecules to “float” in the membrane.
Other Components Proteins Cholesterol Carbohydrates
The Plasma Membrane
Section 2
Proteins
Cellular Structure and Function
Transmit signals inside the cell Act as a support structure Provide pathways for substances to enter and
leave
The Plasma Membrane
Section 2
Cellular Structure and FunctionSection 2
Cellular Structure and Function
Plant and Animal Cell Structures
Structures and Organelles
Section 3
Organelles are bodies within the cytoplasm that serve to physically separate the various metabolic reactions that occur within the cells
1. Nucleus 7. Mitochondria2. Ribosomes 8. Chloroplasts3. Endoplasmic reticulum 9. Cytoskeleton4. Golgi Apparatus 10. Flagella & Cilia5. Lysosomes 11. Centrioles6. Peroxisomes 12. Vacuoles & Vesicles
Cellular Structure and Function
Structures and Organelles
Section 3
Cellular Structure and Function
Structures and Organelles
Section 3
Nucleus
• The nucleus is bounded by the nuclear envelope consisting a phospholipid bilayer, similar to the plasma membrane
• The nucleus contains the DNA (deoxyribonucleic acid), the heredity information of the cellThe nucleus is the brain of the cell
Cells
Nucleus
• Also visible within the nucleus are one or more nucleoli, concentrations of DNA in the process of manufacturing the components of ribosomes
Cells
Ribosomes
• Ribosomes are manufactured in the nucleus and consist of ribosomal RNA and protein
• Ribosomes are the site of protein synthesis
• Ribosomes translate genetic information (DNA) into specific polypeptide chains & proteins
Cells
Endomembrane System
• Composed of the same phospholipid bilayer as the cell membrane
• They are membrane-bound organelles in eukaryotic cells– Similar to the organs of our bodies
• Endomembrane systems only occur in eukaryotic cells
Endomembrane System
• Components of the endomembrane system:– Nuclear envelope– Endoplasmic reticulum– Mitochondria (has 2 lipid bilayers)– Chloroplasts (has 2 lipid bilayers)– Golgi apparatus– Lysosomes– Vacuoles– Vesicles
Endoplasmic Reticulum
• The endoplasmic reticulum or ER, consists of stacks of flattened sacs of membrane
• The best way to determine if the structure is the ER or Golgi apparatus is if it is connected to the nucleus. – ER is connected
Cells
Endoplasmic Reticulum
Cells
Endoplasmic Reticulum
Rough ER Smooth ER
• When ribosomes are present, the ER is called the rough ER and provides
• Aids in protein synthesis
• Smooth ER, without ribosomes, is responsible for the synthesis of lipids and hormones.
Cells
Golgi Apparatus
• The Golgi apparatus– The Golgi modifies and
package proteins and lipids into vesicles
– The Golgi also produces lysosomes
Think of it as Fed Ex
Cells
Mitochondria
• Mitochondria carry out aerobic respiration, a process in which energy (in the form of ATP) is obtained from organic molecules (glucose)– It’s the powerhouse of the cell
• Mitochondria are found in both plant and animal cells
• Since it converts food to usable energy (ATP), what type of cell would have a lot of mitochondria??
Mitochondria
Chloroplasts
• Chloroplasts are specialized organelles found in algae and plants that carry out photosynthesis, the process of capturing energy from sunlight and converting it into useable energy (carbohydrates)
Chloroplasts
Cells
Chloroplasts
• Chloroplasts contain chlorophylls, which are responsible for the green color of a plant and are the key light-trapping molecules in photosynthesis
• Chloroplast are not found in animal cells. Why not??
Chloroplasts and Mitochondria
• Add this to your notes!!!!
• Both chloroplasts and mitochondria have their own circular DNA and ribosomes, just like bacteria
• They also reproduce the same way as bacteria
• This suggests that chloroplasts and mitochondria may have once been bacteria
Vacuoles & Vesicles
• Vacuoles/ Vesicles are fluid-filled membrane bound bodies– They may contain food particles or digestive
enzymes (found in lysosomes)
– Transport substances throughout the cell
– Release of cellular waste products
Vacuoles & Vesicles
• -Central vacuoles are large bodies that store water and occupies most of the interior of plant cells
• -If the central vacuole runs low on water, the plant will begin to wilt
• -The central vacuole in plants stores starch, pigments, and toxic substances
Cells
Lysosomes
• Lysosomes are vesicles from the Golgi apparatus that contain hydrolytic digestive enzymes– They are the cell’s stomach
• Lysosomes play an important role in:– Intracellular digestion such as breaking down
food, cellular debris, and foreign invaders such as bacteria
Lysosomes
Cells
Cytoskeleton
• The cytoskeleton is the internal structure of the cytoplasm and is involved in establishing the shape of the cell and coordinating movements
Cells
Cytoskeleton
Cells
Cilia Short, numerous projections that look like hairs
Cellular Structure and Function
Flagella
Longer and less numerous than cilia
Create movement with a whiplike motion
Structures and Organelles
Section 3
Cellular Structure and FunctionSection 3
Table 7.1 Summary of Cell Structure
Table 7.2 Summary of Cell Structure
Table 7.3 Summary of Cell Structure
Cellular Structure and Function
Plant and Animal Cell Structures
Structures and Organelles
Section 3
Structures only found in Plant Cells
cells: Cell Wall
Chloroplasts
Central Vacuole
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