Prokaryotic Cell Cellular Structure and Function They do not contain membrane-bound organelles Cell Discovery and Theory Steven P. Lynch Section 1

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



Section 1

Eukaryotic Cell More complex structure than prokaryotes


In addition to the prokaryotic structures, eukaryotes also have membrane bound organelles, including a nucleus

Section 1



Section 1

Comparing Prokaryotic and Eukaryotic Cells



The

Section 1

Plasma Membrane Thin, flexible boundary between the cell

and its environment

The Plasma Membrane


Allows nutrients into the cell Allows waste to leave the cell

Section 1

Selective Permeability


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.


A phospholipid molecule is composed of a glycerol backbone, two fatty acid chains, and a phosphate group.

The Plasma Membrane

Section 2


The Plasma Membrane

Section 2

Fluid Mosaic Model


The phospholipid bilayer allows other molecules to “float” in the membrane.

Other Components Proteins Cholesterol Carbohydrates

The Plasma Membrane

Section 2

Proteins


Transmit signals inside the cell Act as a support structure Provide pathways for substances to enter and

leave

The Plasma Membrane

Section 2



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



Section 3



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


Cells


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


Flagella

Longer and less numerous than cilia

Create movement with a whiplike motion


Section 3


Table 7.1 Summary of Cell Structure




Plant and Animal Cell Structures


Section 3

Structures only found in Plant Cells

cells: Cell Wall

Chloroplasts

Central Vacuole

Documents

Prokaryotic Cell Cellular Structure and Function They do not contain membrane-bound organelles Cell Discovery and Theory Steven P. Lynch Section 1