Cellular Biology
Big Idea 4: Biological systems interact, and these systems and their interactions possess complex
properties.
EU 4.A: Interactions within biological systems lead to complex properties.
EU 4.B: Competition and cooperation are important aspects of biological systems.
EU 4.C: Naturally occurring diversity among and between components within biological systems affects interactions with the environment.
EK 4.A.2: The structure and function of subcellular components, and their interactions, provide essential
cellular processes.A. Ribosomes
B. Endoplasmic Reticulum (see 2.b.3)
C. Golgi Complex (see 2.b.3
D. Mitochondria (see 2.b.3)
E. Lysosomes
F. Vacuoles
G. Peroxisomes
H. Nucleus (see 2.b.3)
I. Chloroplasts (see 2.b.3)
J. Cell Wall
K. Cytoskeleton
L. ECM
M. Intercellular Junctions
Stop
RibosomesA. Nonmembrane, universal
structures B. Comprised of two
interacting parts: ribosomal RNA and protein.
C. Site of protein synthesis D. Where the translation of the
genetic instructions yields specific polypeptides.
LysosomesA. Membrane-enclosed sacs
produced by Golgi apparatus
B. Functions1. Intracellular digestion2. Recycling of a cell’s organic
materials3. Programmed cell death
(apoptosis). C. Contain hydrolytic
digestive enzymes.1. Enzymes work best at low
pH (5)2. Membrane pumps in H+
3. Isolates digestion.D. Macrophages use
lysosomes to digest bacteria.
LysosomesE. Autophagy
1. When lysosomes digest parts of cells
2. Important during development (e.g., tadpole tail absorption, degeneration of webbing between human fingers).
F. Missing or inactive lysosomal enzymes cause serious childhood diseases.
1. Pompe’s disease- missing carbohydrase, glycogen accumulates, damages liver.
2. Tay-Sachs disease- missing lipase, lipids accumulate in brain.
VacuolesA. A membrane-bound sac
that plays roles in intracellular digestion and the release of cellular waste products.
B. In plants, a large central vacuole serves many functions
1. Storage of pigments or poisonous substances
2. Cell growth and support3. Alllows for a large surface
area to volume ratio.4. Membrane is called the
tonoplastC. Types include: food,
digestive, and in some protists, water-regulating contractile vacuoles.
PeroxisomesA. Abundant in liverB. Not from
endomembrane. From cytosol proteins and lipids.
C. Transfers hydrogen (from substrates) to oxygen forming hydrogen peroxide(H2O2).
D. Also occur in germinating seeds (glyoxysomes) where they convert oils into sugars
Cell WallA. Mainly cellulose fibers in a
matrix of polysaccharides and proteins.
B. Protect plant cells
C. Prevent water loss.
D. Maintain cell shape
CytoskeletonA. Mechanical support and helps
maintain shape.B. Elements can disassemble and
reassemble in life of a cell.C.Three Types of Fibers
1.Microtubules2.Microfilaments3. Intermediate filaments
MicrotubulesA. Hollow cylindersB. 25 nm in diameterC. Composed of -tubulin and -tubulin
dimersD. Functions
1. Help maintain shape of cells.2. Act as tracks along which
organelles move.a) Motor molecules kinesin and
dynein are associated with microtubules.
b) Motor molecules change shape with ATP.
3. Move chromosomes.4. Make up centrioles in animal cells.
MicrotubulesE. Cilia and Flagella
1. Cilia are short, usually numerous hairlike projections.
2. Flagella are longer, usually fewer, whip-like projections.
3. Composed of a 9 + 2 pattern of microtubules.
MicrofilamentsA. Two chains of actin protein
monomers twisted to form a helix.B. 7 nm in diameterC. Functions
1. Forms a dense complex web just under the plasma membrane.
2. Form microvilli of intestinal cells3. In plant cells, they form tracts
along which chloroplasts circulate.
D. Interaction with myosin1. For muscle contraction2. For pinching off cells during cell
division3. For amoeboid movement.
Intermediate FilamentsA. Rope-like assemblies of
fibrous keratinB. 8-12 nm in diameterC. More permanent than
microtubules and microfilaments.
D. Functions1. Support nuclear
envelope and plasma membrane
2. Form cell-to-cell junctions.
Extracellular Matrix (ECM)A. Mesh of
macromolecules outside plasma membrane of animal cells.
B. Composed mainly of glycoproteins (collagen)- ½ of total protein in vertebrates.
C. Provides support and anchorage for cells.
Intercellular JunctionsA. Plants have Plasmodesmata B. Animal Cells
1. Tight Junctions- Block transport of substances between cells.
2. Desmosomes- Rivet cells together, but still permit transport of substances.
3. Gap Junctions- Two connecting protein rings in adjacent cells.
Endoplasmic ReticulumA. Continuous with outer membrane of
the nuclear envelope.B. Most extensive portion of
endomembrane system.C. Rough endoplasmic reticulum
1. Serves as mechanical support2. Provides site-specific protein synthesis
with membrane-bound ribosomes3. Intracellular transport of protein.4. Makes secretory proteins (mainly
glycoprotiens)5. Packages proteins as transport
vesicles.6. Makes new membranes.
Endoplasmic ReticulumD. Smooth ER (no ribosomes)
1. Synthesizes lipids, phospholipids, and steroids
2. In Liver
a) Converts glycogen to glucose to regulate blood sugar.
b) Detoxifies drugs and poisons (adds hydroxyl groups making them water soluble).
3. Stores Ca+ in muscle
Golgi ComplexA. Membrane-bound structureB. Consists of a series of flattened
membrane sacs (cisternae).C. Synthesis and packaging of
materials (small molecules) for transport (in vesicles)
1. Receives protein-filled vesicles that bud from the ER at cis face.
2. Proteins are modified and repackaged as new vesicles.
3. Vesicles leave from trans face.4. At plasma membrane, they
discharge their contents as secretions.
D. Produces lysosomes.
MitochondriaA. Have a double membrane that
allows compartmentalizationB. Inner membrane is highly
convoluted, forming folds called cristae.1. Cristae contain enzymes
important to ATP production2. Cristae also increase the
surface area for ATP production
C. Sites of cellular respiration.D. Contain ribosomes and their
own DNAE. Specialize in energy capture
and transformation.
NucleusA. Nuclear envelope: a
double membrane that separates nucleoplasm from cytoplasm.
B. Stores genetic information determining structure/function of cells
C. Site where nucleic acids are synthesized
1. Chromatin: Fine strands of DNA and protein (histones)
2. Chromosomes: rod-like structures formed during cell division from coiled or folded chromatin.(46 in humans)
NucleusD. Nucleoplasm
1. Semifluid medium of nucleus2. Has a different pH from
cytosolE. Nucleolus: sites where rRNA
joins proteins to form ribosomes.
F. Nuclear pores (100 nm)- permit passage of certain mRNA and ribosomes
ChloroplastsA. Specialized organelles found in
algae and higher plants that capture energy through photosynthesis.
B. Capture the energy available in sunlight and convert it to chemical bond energy via photosynthesis.
C. Contain Chlorophylls1. Responsible for the green
color of a plant2. The key light-trapping
molecules in photosynthesis.
3. There are several types of chlorophyll, but the predominant form in plants is chlorophyll a.
ChloroplastsD. Have a double outer membrane
that creates a compartmentalized structure
E. Contain membrane-bound structures called thylakoids.
F. Thylakoids are organized in stacks, called grana
G. Energy-capturing reactions1. Produce ATP and NADPH
2. Which fuel carbon-fixing reactions in the Calvin-Benson cycle
3. Carbon fixation occurs in the stroma
4. Where molecules of CO2 are converted to carbohydrates.
ChloroplastsH. Chloroplasts are a type of plastid.
1. Amyloplasts store starch (amylose, amylopectin)
2. Chromoplasts, which contain red and orange pigments.
I. Only plants, algae, and cyanobacteria carry on photosynthesis.
J. There are no chloroplasts in cyanobacteria; chlorophyll is bound to cytoplasmic thylakoids.
Cell TheoryA. Cell is the smallest unit of life
1. Robert Hook (English) 1665 - 1st to observe/name cells (cork,dead)
2. Anton Van Leeuwenhoek (Dutch) 1673- 1st to observe live microorganisms
B. All Organisms are composed of Cells
1. Matthias Schleiden (botanist), 1838
2. Theodor Schwann (zoologist), 1839
C. Cells come from cells1. Rudolf Virchow2. Physician, 1855