Chapter 7: Inside The Cell

Front 1

Cell Theory

Back 1

All organisms consist of cells and all cells are derived from preexisting cells

Front 2

All cells have what?

Back 2

1. Nucleic acids that store and transmit information

2. Proteins that perform most of the cells functions

3. Carbohydrates that provide chemical energy, carbon, support, and identity

4. A plasma membrane, which serves as a selectively permeable membrane barrier

Front 3

Morphology

Back 3

eukaryotic cells have a membrane-bound compartment called a nucleus, and prokaryotic cells do not

Front 4

Phylogeny

Back 4

evolutionary history, organisms are divided into three broad domains called bacteria, archaea, and eukarya

Members of bacteria and archaea are Prokaryotic

Members of the eukarya (algae, fungi, plants, and animals) are Eukaryotic

Front 5

Prokaryotic Chromosome

Back 5

Most bacteria species have a single, circular chromosome that consists of a large DNA molecule associated with a small number of proteins. The DNA molecule contains information, and the proteins provide structural support for the DNA

To fit into the cell, DNA double helix coils on itself with the aid of enzymes to form a compact, "supercoiled" structure.

Front 6

Prokaryotic Nucleoid

Back 6

The location and structural organization of the circular chromosome. The genetic material in the nucleoid is often organized by clustering loops of DNA into distinct domains, but it is not separated from the rest of the cell interior by a membrane.

Front 7

Prokaryotic plasmids

Back 7

Bacterial cells may contain from one to about a hundred small, usually circular, supercoiled DNA molecules called plasmids. Plasmids contain genes but are physically independent of the cellular chromosome

In most cases the genes carried by plasmids are not required under normal conditions, instead, they help cells adapt to unusually circumstances - auxiliary genetic elements

Front 8

Prokaryotic Ribosomes

Back 8

They are observed in all prokaryotic cells are found throughout the cell interior. They are complex structures composed of large and small subunits, each of which contain RNA and protein molecules. "Macromolecule"

Front 9

Prokaryotic photosynthetic components

Back 9

These cells have extensive internal membranes that perform photosynthesis which converts the energy in sunlight into chemical energy stored in sugars. The photosynthetic membranes observed in prokaryotes contain the enzyme and pigment molecules required for these reactions to occur and develop as infoldings of the plasma membrane.

Front 10

Prokaryotic Organelles

Back 10

Recent research indicates that several bacterial species have internal compartments that qualify as organelles.

Organelles is a membrane-bound compartment inside the cell that contains enzymes or structures specialized for a particular function.

They perform an array of tasks including

- storing key molecules

-holding crystals of mineral magnetite

- organizing enzymes responsible for synthesizing complex carbon compounds from carbon dioxide

- sequestering enzymes that generate chemical energy from ammonium ions

Front 11

Prokaryotic Cytoskeleton Structure

Back 11

Bacteria and archaea contain long, thin fibers that serve a variety of roles inside the cell

The cytoskeleton is made up of the protein filaments which help maintain cell shape

Front 12

prokaryotic cytoplasm

Back 12

Inside the plasma membrane (consists of a phospholipid bilayer and proteins) and all the contents of the cell excluding the nucleus are collectively termed the cytoplasm

Front 13

Prokaryotic plasma membrane

Back 13

Consists of a phospholipid bilayer and proteins that either span the bilayer or attach to one side. Because all archaea and virtually all bacteria are unicellular the plasma membrane creates an internal environment that is distinct from the outside, nonliving environment. The combined effect of a lipid bilayer and membrane proteins prohibits the entry of many substances that would be dangerous to life while allowing the passages of molecules and ions required for life

Front 14

Prokaryotic cell wall

Back 14

Bacterial and archaeal cell walls are a tough, fibrous layer that surrounds the plasma membrane. The cell wall resists the hypertonic pressure caused by the high concentration of solutes contained in the cytoplasm.

The cell wall protects the organism and gives it shape and rigidity, much like the exoskeleton of a crab or insect.

Front 15

Prokaryotic Glycolipids

Back 15

lipids that contain carbohydrate groups that acts as another protective layer outside the cell wall

Front 16

Prokaryotic Bacterial Flagella

Back 16

they are assembled from over 40 different proteins at the cell surface of certain species. the base of this structure is embedded in the plasma membrane, and it rotation spins a long, helical filament that propels cells through water.

Front 17

Prokaryotic Fimbriae

Back 17

They are needlelike projections that extend from the plasma membrane of some bacteria and promote attachments to other cells or surfaces.

Front 18

Eukaryotic Cell

Back 18

many species are unicellular but it includes algea, fungi, mold, and animals

Eukaryotic cells are much larger on average than bacteria and archaea

As cell size increases in diameter its volume increases more than its surface area. Since the surface is where the cell exchanges substances with its environment the reduction in the ratio decreases the rate of exchange.

Front 19

Eukaryotic Cytosol

Back 19

The fluid portion between the plasma membrane and these organelles

It is only a fraction of the total cell volume which reduces the effect of the total cell surface-area-to-volume ratio with respect to the exchange of nutrients and waste products

Front 20

How does the compartmentalization in Eukaryotic cells help

Back 20

1. incompatible chemical reactions can be separated.

2. Chemical reactions become more efficient by making it localized and maintained at high concentrations within organelles.

Front 21

Key differences between Eukaryotic and Prokaryotic cells

Back 21

1. Eukaryotic chromosomes are found inside a membrane-bound compartment called the nucleus

2. Eukaryotic cells are often much larger than prokaryotes

3. Eukaryotic cells contain extensive amounts of internal membrane

4. Eukaryotic cells feature a particularly diverse and dynamic cytoskeleton

Front 22

Eukaryotic Nucleus

Back 22

The nucleus contains the chromosomes and functions as an administrative center for information storage and processing. It is the largest and highly organized of all the organelles

Front 23

Eukaryotic nuclear envelope

Back 23

Encloses the nucleus in a complex double membrane

Front 24

Eukaryotic nuclear lamina

Back 24

the nuclear envelope is studded with pore-like openings, and the inside surface is linked to fibrous proteins that form a lattice called nuclear lamina

- the nuclear lamina stiffens the structure and maintains it shape

Front 25

Eukaryotic Nucleolus

Back 25

Chromosomes do not float freely inside the nucleus - instead each chromosome occupies a distinct area, which may vary in different cell types and over the course of cell replication

The nucleus also contains specific sites where gene products are processed and includes at least one distinctive region called the nucleolus where the RNA molecules found in ribosomes are manufactured and the large and small ribosomal subunits are assembled

Front 26

Eukaryotic Ribosomes

Back 26

like bacterial ribosomes eukaryotic ribosomes are complex macromolecular machines that produce proteins. They are not classified as organelles because they are not surrounded by membranes

Front 27

Eukaryotic Endoplasmic Reticulum

Back 27

portions of the nuclear envelope extend into the cytoplasm to form an extensive membrane-enclosed factory called ER.

The ER membrane is continuous with the nuclear envelope - it has both the rough and smooth ER

Front 28

Eukaryotic The rough endoplasmic RER

Back 28

Rough ER- named for its appearance in transmission electron micrographs.

The ribosomes associated with the rough ER synthesize proteins that will be inserted into the plasma membrane, secreted to the cell exterior or shipped to an organelle

Front 29

Eukaryotic Lumen

Back 29

The interior of the rough ER, like the interior of any sac-like structure in a cell or body is called the lumen. The lumen of the rough ER newly manufactured proteins undergo folding and other types of processing

Front 30

Eukaryotic Smooth Endoplasmic Reticulum

Back 30

parts of the ER that are free of ribosomes. The smooth ER contains enzymes that catalyze reactions involving lipids. Depending on the type of cell, these enzymes may synthesize lipids needed by the organism or break down lipids and other molecules that are poisonous

Front 31

Eukaryotic Golgi apparatus

Back 31

The products of the rough ER pass through the Golgi apparatus before they reach their final destination. The Golgi apparatus consists of discrete flattened membranous sac called cisternae which are stacked on top of one another

- Has the cis surface closes to the nucleus and the trans surface which is oriented toward the plasma membrane

- the cis side receives products from the rough Er and the trans side ships them

- in the cisternae the rough ER products are processed and packaged for delivery

Front 32

Eukaryotic Lysosomes

Back 32

Animal cells contain organelles called lysosomes that function as recycling centers. Lysosomes contain about 40 different enzymes, each specialized for hydrolyzing different types of macromolecules- proteins, nucleic acids, lipids, or carbohydrates. They leave from the organelles membrane

Front 33

Eukaryotic endomembrane system

Back 33

Even though lysosomes are physically separated from the Golgi apparatus and the endoplasmic reticulum, these various organelles jointly form a key functional grouping referred to as the endomembrane system.

It is a center for producing, processing, and transporting proteins and lipids in eukaryotic cells.

Front 34

Eukaryotic Vacuoles

Back 34

The cells of plants, fungi, and certain other groups lack lysosomes. Instead they contain prominent organelles called a vacuole.

The vacuoles are large. some contain enzymes specialized for digestion most however act as storage deposits

the cytoplasm pushes the plasmid membrane against the cell wall whcih maintains the plants cell shpe.