Summary
Summary BIOL 141 Unit 2 Study Guide
- Course
- Biol 141
- Institution
- University Of Maryland - Baltimore County
Detailed unit 2 Study Guide for Biol 141.
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BIOL 141 Exam 2 Study GuideChapter 7
1. What components are found in both prokaryotic and eukaryotic cells? What are the functions of these
components?
● Chromosome: consists of large DNA molecule associated with small number of proteins (DNA
molecule contains information, proteins provide structural support)
● Genes → DNA → chromosome
● Ribosomes: (protein manufacturer) complex structures composed of large and small subunits
each of which contains RNA and protein molecules
● Plasma membrane
● Ctyoplasm
2. What are the major differences between prokaryotic and eukaryotic cells?
Eukaryotic:
● Much larger
● Contain nucleus
● Chromosomes found in nucleus
● Extensive amounts of internal membrane
● Diverse and dynamic cytoskeleton
● Plasmids are rare
● Many types of organelles
● flagella
Procaryotic:
● Cell wall
● Chromosome/DNA found in nucleoid
● Plasmids are common
3. What components are found only in eukaryotic cells? What are the functions of these components?
● Centrioles (only animal cells)
● Vacuoles: bigger than lysosomes, store, sometimes draw in water from outside when ion
concentration (K+ and Cl-) is high and expand against cytoplasm which expands against
plasma membrane against cell wall to maintain cell shape
● Lysosomes: (recycling centers/waste bins/digestion) contains about 40 different
enzymes, each specialized for hydrolyzing proteins, nucleic acids, lipids, or
carbohydrates. The amino acids, nucleotides, sugars, etc produced leave the lysosome via
transport proteins through membrane. Once in cytosol, they can be used as sources of
energy/building blocks for new molecules
● Nucleus: contains chromosomes and functions as administrative center for information
storage and processing
● Golgi apparatus: (UPS store) products of rough ER pass through golgi apparatus before
final destination; consists of flattened, membranous sacs (cisternae) stacked on top of
each other; in cisternae rough ER products are processed/packed for delivery
, ○ Cis-closer to nucleus, receives products from rough ER
○ Trans-closer to plasma membrane, ships products out to other organelles/cell
surface
● Rough ER: (protein manufacturing center) ribosomes from rough ER make proteins that
will be inserted into the plasma membrane, secreted to the cell exterior, or shipped to an
organelle; functions of proteins produced: carry messages to others, act as membrane
transport proteins/pumps, enzymes
● Smooth ER: (lipid processing center) contains enzymes that catalyze rxns involving
lipids, may synthesize lipids needed by the organism/break down lipids and other
molecules that are poisonous; manufacturing site for phospholipids used in plasma
membrane; functions as reservoir for Ca2+ ions that act as a signal triggering an array of
activities inside the cell
● Mitochondria: (powerhouse of the cell/ATP synthesizer) produces ATP; inner membrane
connected to series of sac-like cristae
○ Mitochondrial matrix: solution enclosed within inner membrane
● Peroxisomes: (redox reaction center) globular organelles that have a singular membrane
and originate as buds from the ER; example-peroxisomes in your liver remove electrons
(or oxidize) the ethanol in alcoholic beverages; make specialized set of oxidation rxns
possible and safe for the cell
● Chloroplast (plant cells): organelle in which sunlight is converted to chemical energy
during photosynthesis, double membrane around exterior
○ Thylakoids: membrane-bound, sac-like structures that dominate the interior of
the chloroplast (independent of inner membrane), many of “machines”
responsible for converting light energy into chemical energy are embedded in the
thylakoid membranes
○ Stroma: region outside thylakoids that contains enzymes that use chemical
energy to produce sugars
4. What are the advantages of compartmentalization in organelles?
● Incompatible chemical reactions can be separated: For example, new fatty acids can be
synthesized in one organelle while excess or damaged fatty acids are degraded and recycled in a
different organelle
● Chemical reactions become more efficient: The substrates required for particular reactions can
be localized and maintained at high concentration within organelles. If substrates are used up in a
particular part of the organelle, they can be replaced by substrates that have only a short distance
to diffuse. Groups of enzymes that work together can be clustered within or on the membranes of
organelles instead of floating free in the cytosol. When the product of one reaction is the substrate
for a second reaction catalyzed by another enzyme, clustering the enzymes increases the speed
and efficiency of both reaction sequences.
5. How does the nuclear envelope differ from the plasma membrane? How do molecules move between
the cytoplasm and the nucleus?
The nuclear envelope separates the nucleus from the rest of the cell. The plasma membrane
maintains the intracellular environment. The plasma membrane is selectively permeable lipid
bilayer. Molecules move through nuclear pores.
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