Exam 2 Flashcards
Cell Theory
- All organisms are composed of one or more cells; and the life processes of metabolism and heredity
- Cells are the smallest living thigs, the basic units of organization in all living things
- New cells arise only by divsion of existing cells
Similarties found in all Cells
- Centrally located genetic material, genetic instructions are valuable
- Cytoplasm Fluid filled matrix liquid (cytosol), specialized structures (organelles)
- Ribosomes Molecular machines to convert genetic info into protein machines
- Plasma membrane controlled spaces apart from the environment
Prokaryotes
“Before Kernal”, no nucleus
Eukaryotes
“After Kernal”, has nucleus
Features of Prokaryotes
-Relativley simple
-Encased by a strong/rigid cell wall
-Interiors are very dense w/ proteins, genetic material, etc.
-Interior pressure is high
-Osmosis causes changes in cell pressure
-Invaders are densely packed, osmosis causes high pressure
-Do not have membrane-bound organelles
-Often have flagella
Features of Eukaryotes
-Contain their genetic material inside a nucleus
-Organelles define the interior structure of Eukaryotes
Nucleus
-Cell’s information center
-Wrapped in membrane
-Pores allow material into and out of the nucleus (Very selctive pores, RNA out, nucleotides in)
-Nucleolus is the primary site of ribosome production
Ribosomes
*Cell’s protein-making machines
*Two subunits clamp onto a strand of RNA
* Read RNA to add amino acids and thereby make proteins
Ribosomes (Free floating)
- Cell’s protein making machines
-Proteins made by ribsomes free-floating in the cytoplasm are destined for targets also free-floating in the cytoplasm
-Proteins floating in the cytosol
-Proteins moving into the nucleus
Endoplasmic Reticulum
-Within the cytoplasm
- A little “network”
-About 10,000 in each cell
-Two major portions (Rough ER or RER and Smooth ER or SER)
Rough ER
*Site of protein making
*Coated with ribsomes
* Proteins made on membrane of the RER are destined for membrane bound targets
*Embedded in Plasma membrane
*Exported from the cell
* Sent to other organelles
Smooth ER
Make lipids
Sent lipids to membranes (cell membrane organelles)
Smooth surface because no ribosomes are present
Golgi Apparatus
-Sorts and packages proteins for transport
-Post office of the cell
-Sorts, packages, and distributes
-Materials arrive at the CIS Face and Deport at the Trans Face
-Proteins depart in secretory vesicles (blister)
Lysosomes
*Degradation and recycling
*Acidic interior
*Break down molecules brought into the cell through endocytosis (“within cell”)
*Break down “food” brought into the cell through phagocytosis (“eat cell”)
*Break down old organelles through autophagy (“self-eating”)
Vacuoles
-Blank Space
-Contains water and other things to help plant cells maintain osmotic balance
Mitochondrion
-Genetics (ATP) to power the cells needs creations
-Contain their own DNA and protein synthesis machines (ribosomes)
-Surrounded by a double membrane
-Intermembrane space matters a lot for mitochondrion function
Chloroplasts
-Use light to make food
-Plants can make their own food
-Contain chlorophyll pigment that gives plants their green color
-Surrounded by a double membrane
-Structure (spaces) matters a lot for chloroplast function
-Grana, Thylakoids
-Chlorophyll pigments lie on the surface of the thylakoid
Cytoskeleton
*Supports and shapes cells
*Three kinds of fibers: Actin filaments, Microtubules, Intermediate filaments
*Supports and shapes cells
*Provides “highways” for transport
Cell Wall
-Provides protection and support
-Plants, fungi, many types of bacteria
-Different structure than prokaryotic cell walls
-Made of sugar (cellulose) and protein (Chitin)
Overview of Euakaryotes vs. Prokaryotes
- Prokaryotes have a free-floating chromosome
- Eukaryotes enclose chromosomes within a membrane-enclosed nucleus
- Eukaryotes often much larger
- Eukaryotes contain lots of internal compartments
- Eukaryotes have a diverse, dynamic cytoskeleton
- Eukaryotes cells have many diverse organelles whereas prokaryotes have few or none
Organelle
Membrane-bound compartment in cytoplasm
Endosymbosis
Same life within
How did Eukayotes start?
The idea that mitochondria and chloroplasts originated from bacteria that took up residence within a primordial eukaryote cell
Mitochondria and Chloroplasts contain…
DNA coils with similar sequence as DNA in bacteria
Euk organelles mito and chloroplasts have a
double membrane
One possible way through which eukaryotes could have developed extensive compartmentalization
Endosymbosis
Compartmentlization
-Many small, specialized spaces
-Structures within a cell specialized for specific functions
Advantages
-Incompatible regions can be separated
-Efficiency of reactions is increased
Disadvantages
-Movement between spaces can be tough
-Making walls is “expensive” (molecular machinery to make lipids)
Energy
-Potential to do work
-Can be found in many forms
-Conservation of energy (for example potential and kinetic energy)
Energy in Biochemical Reactions
-Photosynthesis and cellular respiration
-Cells use ATP to power the reactions of cellular metabolism
-ATP consists of 3 phosphate groups (TRI), a ribose, and an adenine
-Energy is released when ATP is hydrolyzed (hydrolysis reactions) into ADP
-ATP use and recharging is a primary mechanism of reaction coupling
Electrons and Bond Energy
-Electrons act as energy carriers
-Electrons have energy levels
-Different shells have different energy levels
-But when an electron is present, it brings with it some energy
-Key goal in understanding reactions–>watch where electrons move
- Electrons act as carriers
Energy stored in C-H Bonds is a primary way…
that energy is stored in carbohydrates and fats
The “stuff” of chemical bonds
Electrons