Chapter 3 Review (13 questions) Flashcards
What are the 4 basic concepts of the cell theory
Cells are the building blocks of all plants and animals
All cells come from the division of preexisting cells
Cells are the smallest units that perform all vital physiological functions
Each cell maintains homeostasis at the cellular level
What are the 4 general functions of the cell membrane
- Physical isolation barrier between cell interior and surrounding extracellular fluid (a.k.a. interstitial fluid)
- Regulation of exchange with the environment
¥ Ions and nutrients enter
¥ Waste and cellular products released - Sensitivity to the environment facilitates communication, receives information about the cell’s surroundings
¥ Extracellular fluid composition, chemical signals - Structural support anchors cells and tissues
What are the 6 general functions performed by membrane proteins
- Anchoring Proteins (stabilizers) attach to other structures, can attach inside or outside of cell
- Recognition Proteins (identifiers) label cells as normal or abnormal
- Enzymes catalyze reactions
- Receptors bind and respond to ligands (ions, hormones)
- Carriers transport specific substances across membrane
- Channels create a pore for water and solute transport
What are the 4 general functions of the glycocalyx
¥ Lubrication and Protection
¥ Anchoring and Locomotion
¥ Specificity in Binding (receptors)
¥ Recognition (immune response)
Be able to identify phospholipids, glycolipids, integral proteins, peripheral proteins, glycoproteins, and cholesterol in a figure of the plasma membrane.
¥ Phospholipid bilayer creates a barrier to ions, water, and large or polar molecules
¥ Hydrophilic heads exposed to the aqueous environment on both sides (extracellular fluid, cytosol)
¥ Hydrophobic fatty-acid tails buried inside membrane
¥ Integral proteins embedded within the membrane
Peripheral proteins bound to inner or outer surface of the membrane
• What are the major nonmembranous organelles? membranous organelles?
¥ Nonmembranous organelles no membrane
¥ Include the cytoskeleton, microvilli, centrioles, cilia, ribosomes, and proteasomes
¥ Membranous organelles enclosed by membrane
¥ Include the endoplasmic reticulum (ER), the Golgi apparatus, lysosomes, peroxisomes, and mitochondria
• Describe the general structure and function of the cytoskeletal filaments (microfilaments, intermediate filaments, microtubules)
¥ Microfilaments smallest filaments built from the protein actin, generally peripherally located
¥ Intermediate filaments mid-sized, stabilize the positions of organelles, anchor to surrounding cells
¥ Microtubules large hollow tubes built from the protein tubulin, cell strength, vesicle transport, cell division (spindle)
• Describe the structure and function of microvilli, centrioles, and cilia.
¥ Microvilli finger-like projections of the cell membrane
¥ Increase surface area for absorption
¥ Centrioles built from 9 microtubule triplets
¥ Centrioles form spindle apparatus during cell division
Cilia long thin extensions from the cell membrane built from microtubule triplets
• Describe the structure and function of ribosomes. Where in a cell are ribosomes located?
Ribosomes build polypeptides
- Free ribosomes in cytoplasm manufacture proteins for cell
- Fixed ribosomes attached to ER manufacture proteins for secretion
• What is the function of a proteasome?
Proteasomes degradative function
¥ Disassemble damaged proteins for recycling
• Describe the structure, location, and the 4 major functions of the endoplasmic reticulum.
¥ Connected to nuclear membrane
Functions
1. Synthesis of proteins, carbohydrates, and lipids
2. Storage of synthesized molecules and materials
3. Transport of materials within the ER
4. Detoxification of drugs or toxins
o What functions are performed by the smooth ER?
¥ No ribosomes attached
¥ Synthesizes lipids and carbohydrates
¥ Phospholipids and cholesterol (membranes)
¥ Steroid hormones (reproductive system)
¥ Glycerides (storage in liver and fat cells)
¥ Glycogen (storage in muscles)
o What functions are performed by the rough ER?
¥ Surface covered with ribosomes
¥ Active in protein and glycoprotein synthesis
¥ Facilitates polypeptide folding into correct protein structures
¥ Encloses products in transport vesicles
• Describe the structure and function of the Golgi apparatus, lysosomes, and peroxisomes.
Golgi Apparatus protein modification and sorting
Functions
1. Modifies and packages secretions
¥ Hormones or enzymes
¥ Released through exocytosis
2. Renews or modifies the plasma membrane
3. Packages special enzymes within vesicles for use in the cytoplasm
Lysosomes powerful enzyme-containing vesicles degrade old organelles, extracellular materials, damaged cells
Peroxisomes enzyme-containing vesicles
¥ Break down fatty acids, organic compounds
¥ Produce hydrogen peroxide (H2O2)
• What process connects many membranous organelles to one another?
Membrane Flow is a continuous exchange of membrane parts by vesicles
¥ All membranous organelles (except mitochondria)
¥ Nuclear envelope, RER, SEM, transport vesicles, Golgi, secretory vesicles, cell membrane, endosomes, lysosomes, peroxisomes are all interconnected
¥ Allows adaptation and change
• Describe the structure and function of the mitochondrion.
¥ Structure outer membrane, inner membrane, cristae, matrix
¥ Function transform energy stored in “food” molecules into energy stored in ATP
¥ Glycolysis, citric acid cycle, electron transport chain, aerobic metabolism
• Describe the structure and function of the nucleus.
Nucleus information storage and retrieval
¥ Largest organelle
¥ Structure nuclear envelope, nuclear pores, nucleoli
¥ Function the DNA within the nucleus has all the information to build and “run” the organism
o How is DNA organized within the nucleus?
Contents of the Nucleus
¥ Chromatin Loosely coiled DNA and structuring proteins (cells not dividing)
¥ Chromosomes tightly coiled DNA (cells dividing)
• The synthesis of a protein requires gene activation, transcription, and translation. What happens during each of these steps?
Protein Synthesis requires
- Gene activation uncoiling DNA to access information
- Transcription copying information from DNA to mRNA
- Translation interpreting information in mRNA to build polypeptide
• What signals RNA polymerase to start and end transcription?
¥ Promoter base sequence reads “start here”
¥ Terminator base sequence reads “stop here”
¥ RNA polymerase produces messenger RNA (mRNA)
¥ Pre-mRNA is “edited” during RNA processing