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