AP BIOLOGY CHAPTER 6: A TOUR OF THE CELL

Light microscopes
Microscopes that focus light beams by using glass lenses

Resolution & Specimen of Light Microscopes
Microscopes that don’t have high resolutions, but are used to study living specimen

Electron microscopes (EM)
Microscopes that focus electron beams using electromagnets

Resolution & Specimen of EM
High resolutions which can only be used on dead specimen

TEMs
Transmission electron microscopes; used to study internal cell structures by making thin slices

SEMs
Scanning electron microscopes; useful for studying surface structures

4 things that all cells have
Plasma membranes, cytoplasm, chromatin, & ribosomes

Major difference between prokaryotic & eukaryotic cells
Nucleoid & nucleus

As a cell increases its size, ____________.
Its volume increases faster than its surface area

Cell membrane
Functions as a selective barrier that allows the passage of oxygen, nutrients, and wastes for the whole volume of the cell

The general structure of a biological structure
Nucleus

Where genes are located in the cell
Nucleus, mitochondria, and chloroplast

Double membrane that separates nucleus from cytoplasm
Nuclear envelope

Within the nucleus, discrete units that organize DNA and associated proteins & carry genes
Chromosomes

Fibrous material that is a complex of proteins & DNA
Chromatin

A region of densely stained fibers and granules adjoining chromatin (located in the nucleus)
Nucleolus

Ribosomes
Organelles that carry out protein synthesis; contain rRNA & protein

Where free ribosomes are located
Cytoplasm

What free ribosomes make
In-house proteins for the cell

Where bound ribosomes are located
Rough endoplasmic reticulum

what bound ribosomes make
Export proteins & membranes

6 parts of the endomembrane system
Nuclear membrane, ER, Golgi body, lysosomes, vacuoles, & cell membrane

Smooth ER
no ribosomes; creates lipids

Rough ER
ribosomes; creates proteins

Golgi body
center for packaging & transporting things

Vesicles
Where the Golgi sorts and packages materials

Lysosome
membrane-bound sac of hydrolytic enzymes that an animal cell uses to digest macromolecules

Apoptosis
Programmed cell death

Vacuoles
membrane-bound sacs that store food & water in cells

Nuclear membrane
A highly-porous membrane that separates the nucleus from the cytoplasm

Endoplasmic reticulum
a cell structure that forms a maze of passageways in which proteins and other materials are carried from one part of the cell to another

Cell membrane
thin, flexible barrier around a cell; regulates what enters and leaves the cell

Tonoplast
Large central vacuole located in mature plant cells

Mitochondria
sites of cellular respiration, generating ATP from the catabolism of sugars, fats, and other fuels int he presence of oxygen

Chloroplasts
Found in plants and algae; sites of photosynthesis: convert solar energy to chemical energy and synthesize new organic compounds such as sugars from CO2 & H2O

Mitochondria and Chloroplasts
Not part of the endomembrane system

Reasons why M & C are not part of the ES
-2 membranes
-have ribosomes/circular DNA attached to inner membrane
-creates its own proteins
-semi-autonomous organelles

Amyloplasts
Colorless plastids that store starch in roots and tubers (like potatoes)

Chromoplasts
Store pigments for fruits (like red peppers) and flowers

Chloroplasts
Contain the green pigment chlorophyll that functions in the photosynthetic production of sugar

Stroma
Fluid-filled space inside the innermost membrane that contains DNA, ribosomes, & enzymes

Thylakoids
Floating flattened membranous sacs that play a critical role in converting light to chemical energy

Grana
Thylakoids stacked like poker chips

Peroxisome
Single membrane; contains an enzyme that converts H2O2 to H2O

What peroxisomes break down
fatty acids to smaller molecules that are transported to mitochondria as fuel for cellular respiration

Cytoskeleton
network of fibers that organizes structures and activities in the cell

3 things the cytoskeleton provides
Support, cell shape, and anchorage

3 main types of fibers composing the cytoskeleton
-Microtubules
-Microfilaments
-Intermediate filaments

Dynein
In cilia and flagella, a large contractile protein extending from one microtubule doublet to the adjacent doublet. ATP hydrolysis drives changes in dynein shape that lead to bending of cilia and flagella.

9+2 pattern
nine doublets of microtubules, the members of each pair sharing walls, and arranged in a ring. in the center of the ring are two straight microtubules. found in cilia and flagella

Intercellular junctions
help integrate cells into higher levels of structure and function

Plasmodesmata
Channels allowing cytosol to pass between plant cells

Animal cells’ 3 main types of intercellular links
-tight junctions
-desmosomes
-gap junctions

Tight junctions
Membranes of adjacent cells are fused, forming continuous belts around cells; prevents leakage of extracellular fluid

Desmosome
(anchoring junctions) fasten cells together into strong sheets, much like rivets

Gap junctions
(communicating junctions) provide cytoplasmic channels between adjacent cells (similar to plasmodesmata in plant cells)

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