Quiz 10/21-- Cell Anatomy and Membrane Transport

Eukaryotes and prokaryotes

Eukaryotes: have membrane-bound nucleus

Prokaryotes: lack membrane-bound nucleus

Are these organisms prokaryotic of eukaryotic?

Bacteria, Archaea, Eukarya

1. Bacteria—prokaryotic

2. Archaea—prokaryotic

3. Eukarya—eukaryotic

What are Bacteria, Archaea, and Eukarya?

the three domains of organisms

prokaryotic cell

a simple, single-celled (unicellular) organism that lacks a nucleus, or any other membrane-bound organelle.

They have…

• Contain at least one chromosome

• Many protein-synthesizing ribosomes

Many prokaryotes have internal _______ membranes:

photosynthetic

What do prokaryotes’ internal photosynthetic membranes do?

• Convert energy in sunlight to chemical energy

• Multiple membranes passing through internal region of cell observed in photosynthetic bacteria

• Develop as infoldings of plasma membrane

• Contain enzymes and pigment molecules required for reactions to occur

Prokaryote Cell Wall

forms a protective “exoskelton”

Most prokaryotes have a cell wall that…

• is composed of tough, fibrous layer

• Surrounds plasma membrane

• Protects shape and rigidity of cell

In bacteria cell walls…

• Primary structural component of cell wall = polysaccharide peptidoglycan

• Some have outer membrane made of glycolipids

• Many prokaryotes interact with their environment via…

• structures that grow from their plasma membrane

• Flagella

• Structure found on bacterial surfaces

• long filaments that rotate to propel cell

Fimbriae

• Structure found on bacterial surfaces

• needle-like projections that promote attachment to other cells or surfaces

Eukaryotic cell

has a membrane-bound nucleus

• and other membrane-bound compartments or sacs, called organelles, which have specialized functions.

Eukaryotic Cell Anatomy: The Plasma Membrane

made up of a phospholipid bilayer with embedded proteins that separates the internal contents of the cell from its surrounding environment.

Eukaryotic Cell Anatomy: The Cytoplasm

comprises the contents of a cell between the plasma membrane and the nuclear envelope

Many metabolic reactions, including protein synthesis, take place here.

Eukaryotic Cell Anatomy: Cytoskeleton

a network of protein fibers

helps to maintain the shape of the cell

secures certain organelles in specific positions

allows cytoplasm and vesicles to move within the cell

enables unicellular organisms to move independently

Eukaryotic Cell Anatomy: Flagella and Cilia

Flagella (singular = flagellum) are long, hair-like structures 

Cilia (singular = cilium) short, hair-like structures 

Eukaryotic Cell Anatomy: Vesicles and Vacuoles

Vesicles and vacuoles are membrane-bound sacs that function in storage and transport.

Eukaryotic Cell Anatomy: The Central Vacuole

• plays key role in regulating the cell’s concentration of water

• In plant cells, the vacuole also provides internal structural support → more water in vacuole pushes against cell wall

Eukaryotic Cell Anatomy: The Nucleus

houses the cell’s DNA in the form of chromatin and directs the synthesis of ribosomes and proteins.

Eukaryotic Cell Anatomy: nuclear envelope

a double-membrane structure that constitutes the outermost portion of the nucleus

Eukaryotic Cell Anatomy: Nucleolus

assembles the ribosomes

Location where ribosomal R N A is synthesized and ribosome subunits are assembled

Eukaryotic Cell Anatomy: The Endomembrane System

a group of membranes and organelles in eukaryotic cells that work together to modify, package, and transport lipids and proteins.

Eukaryotic Cell Anatomy: Ribosomes

the cellular structures responsible for protein synthesis

Eukaryotic Cell Anatomy: The Endoplasmic Reticulum

a series of interconnected membranous tubules that collectively modify proteins and synthesize lipids.

Eukaryotic Cell Anatomy: Rough ER

• has ribosomes attached to its cytoplasmic surface

Eukaryotic Cell Anatomy: Smooth ER

• is continuous with the RER but has few or no ribosomes

Eukaryotic Cell Anatomy: Golgi Apparatus/ Golgi Body

• a series of flattened membranous sacs

Eukaryotic Cell Anatomy: Lysosomes

cell’s “garbage disposal.” Digestive enzymes within the lysosomes aid the breakdown

Eukaryotic Cell Anatomy: Peroxisomes

Carry out oxidation reactions that break down fatty acids and amino acids. They also detoxify many poisons that may enter the body.

Eukaryotic Cell Anatomy: Mitochondria

for making adenosine triphosphate (ATP), the cell’s main energy-carrying molecule.

Eukaryotic Cell Anatomy: Chloroplasts

function in photosynthesis

can be found in eukaryotic cells such as plants and algae.

In photosynthesis, carbon dioxide, water, and light energy are used to make glucose 

Eukaryotic Cell Anatomy: Endosymbiosis Theory

• Proposes that mitochondria and chloroplast were once free-living bacteria

• Bacteria were engulfed by ancestor of modern eukaryotes but were not destroyed

• Mutually beneficial relationship evolved

Eukaryotic Cell Anatomy: Endosymbiosis Theory: Like mitochondria, chloroplasts contain their own D N A and manufacture their own ______s:

• Chloroplasts and mitochondria grow and divide ________

ribosomes

independently of cell division

Eukaryotic Cell Anatomy: The Cell Wall

• Cell walls rigid coverings that protect the cell, provide structural support, and give shape to the cell.

Eukaryotic Cell Anatomy: The Cell Wall

What are plant cell walls made of?

Bacteria?

Fungi?

• Plants = Cellulose

• Bacteria = Peptidoglycan

• Fungi = Chitin

Eukaryotic Cell Anatomy: Animal Cells versus Plant Cells

• Cell wall: Plant cells have one; animal cells do not.

• Chloroplasts: Plant cells use these for photosynthesis; animal cells do not have them.

• Vacuoles: Plant cells typically have one large central vacuole; animal cells usually have smaller ones.

• Both: Plant and animal cells are eukaryotic, meaning they have a nucleus and membrane-bound organelles.