________ microscope - minimum resolution is - 2 microns ( the size of a small bacterium) CHAPTER 6 A TOUR OF THE CELL For higher resolution- -____________microscope -Transmission Electron Microscope -Scanning Electron Microscope Microscopy Fig. 6.2

Prokaryotic vs eukaryotic cells 1. Prokaryotic and eukaryotic cells differ in size and complexity Similarities- A ___________________. A ________(semifluid substance) within the cell ________________ ___________- organelles that make proteins Differences Euks have chromosomes in a _________(compared to a nucleosome in proks.) Euks have many _________ __________________ Eukaryotic cells are ___________ times larger Larger organisms do not generally have______cells than smaller organisms - simply _______ cells.

Fig. 6.6 The prokaryotic cell is much simpler in structure, lacking a nucleus and the other membrane-enclosed organelles of the eukaryotic cell. Prokaryote components

The _________________- functions as a selective barrier that allows passage of oxygen, nutrients, and wastes for the whole volume of the cell. Fig. 6.8

Animal cell Animal cells lack: ___________ Fig. 6.9

Plant cell Plant cells lack: __________ Most other components are ________ by plant and animal cells

contains most of the _______ in a eukaryotic cell. Some genes are in _________________and _____________ separated from the cytoplasm by a _________membrane. Protein pores allow large macromolecules and particles to pass through. ___________ (located internal to the membrane)- maintains nuclear _________ 1. The ___________ Fig. 6.10

___________ (DNA and associated proteins) Each eukaryotic species has a characteristic number of ____________ A typical human cell has 46 chromosomes, but sex cells (eggs and sperm) have only 23 chromosomes. ___________- densely stained fibers and granules adjoining chromatin Factory for ribosomal RNA (rRNA) rRNA is a component of _______________. 1. The nucleus (cont.) Fig. 6.10

_________________- contain _______ (from nucleolus) and _________. composed of two subunits carry out _________ synthesis. 2. ________________ build a cell’s proteins Fig Ribosomes

Found in ____locations- 1. ________ ribosomes -suspended in the cytosol Function: synthesize ___________ proteins 2__________ ribosomes- attached to the outside of the _____________________ Function: synthesize __________ proteins and ____________ proteins Note: Ribosomes can shift locations. Ribosomes- (cont.)

Accounts for ½ the membranes in a eukaryotic cell. Includes membranous tubules and internal, fluid- filled spaces, the ________. The ER membrane is continuous with the ________________ 3. The endoplasmic reticulum (ER) Function: Manufactures ____________ Fig. 6.12

Two regions of ER that differ in structure and function. _________ ER lacks ribosomes Function: synthesize lipids, including oils, phospholipids, and steroids Also detoxifies drugs and poisons _________ ER ribosomes attached to the outside Packages proteins into ________ _____________ Fig The endoplasmic reticulum (cont.)

Endoplasmic reticulum Ribosomes Nucleus Review

Function: Finishes, sorts, and ships _____________ Many transport vesicles from the ER travel to the _______________________ for modification of their contents. 4. The Golgi apparatus structure contains __________ – looks like a stack of pita bread. Cis face “receiving” Trans face “shipping” _____ face _______ vesicles from ER; ______ face ships vesicles out Fig. 6.13

a membrane-bounded sac of ___________ enzymes functions -digest ___________________ (proteins, fats, polysaccharides, and nucleic acids). Low pH (5.0) 5. _______________ Fig. 6.14a massive leakage from lysosomes can destroy an cell by ______________ Nucleus Lysosome

5. Lysosomes (Cont.) The lysosomal enzymes and membrane are synthesized by __________ and then transferred to the ________. At least some lysosomes bud from the trans face of the Golgi. Fig. 6.16

Inherited diseases affect_____________ metabolism: These individuals lack a functioning version of a normal hydrolytic enzyme. Result- Lysosomes are engorged with __________________ substrates. ____________disease in the liver Tay-Sachs disease in the brain. Lysosomes can fuse with ________________ or other organelles 5. Lysosomes (Cont.)

Vesicles and vacuoles (larger versions) are membrane-bound ____ with varied functions. _____ vacuoles, from phagocytosis, fuse with lysosomes. ______________ vacuoles, found in freshwater protists, pump excess water out of the cell. ___________ vacuoles are found in many mature __________ cells. Functions - stockpiling proteins or inorganic ions, depositing metabolic byproducts, storing pigments, and storing defensive compounds against herbivores. 6. _____________ Fig. 6.15

Convert energy to forms that cells can use for work. _____________ -site of __________ _____________, generating ATP from the catabolism of sugars, fats, and other fuels in the presence of oxygen. Chloroplasts, found in plants and eukaryotic algae, are the site of _________________. They convert solar energy to chemical energy and synthesize new organic compounds from CO 2 and H 2 O. 7. ______________ and ________________ Chloroplast Mitochondria Fig Fig. 6.18

Mitochondria and chloroplasts- Proteins from _____ ribosomes in the cytosol (and a few from their own ribosomes). Contain DNA Grow and reproduce as ________________ organelles. Almost all _____________ cells have mitochondria. Cells may contain one to ________________. The number of mitochondria is correlated with aerobic metabolic activity. 7. Mitochondria and Chloroplasts (Cont.)

The chloroplast is a type of ______. ______plasts- store starch in roots and tubers. _______plasts- store pigments for fruits and flowers. _______plast- produces sugar via photosynthesis. Chloroplasts gain their color green pigment chlorophyll. The ______ in the chloroplast is separated from by two ___________. contains DNA, ribosomes, and enzymes for part of photosynthesis. 7. Mitochondria and Chloroplasts (Cont.) Fig. 6.18

generate and degrade _________________ (H 2 O 2) in performing various metabolic functions H 2 O 2 is ______, but the peroxisome has another enzyme that converts H 2 O 2 to water. 8. _______________ Functions: break _____________ down for fuel. ________ alcohol (and other harmful compounds). Convert the fatty acids in seeds to sugars Fig. 6.9

The _________________ is a network of_______ extending throughout the cytoplasm. Functions: Organizes the structures and activities of the cell. Provides _________________ support and maintains shape of the cell. Provides______________ for many organelles and cytosolic enzymes dynamic 9. Cytoskeleton Fig. 6.20

There are three main types of fibers in the cytoskeleton: _______________ ________________ ___________________. 9. Cytoskeleton (Cont.) Fig. 7.21b microfilaments Intermediate filaments (Keratin) (Actin) Fig. 6.26

Function in plants: protection, maintains its shape, and prevents excessive uptake of water. It also supports the plant against the force of gravity. 10. Cell wall – Plant and proks, but not _________ cells Composed of microfibrils of _______ embedded in a matrix of proteins and other polysaccharides. steel-reinforced concrete analogy Fig. 6.28

Can influence the activity of genes in the nucleus via a combination of chemical and mechanical signaling pathways. This may coordinate all the cells within a tissue. Function- support, adhesion, movement, and regulation Animals cells have an elaborate _____. _______ fibers embedded in a network of __________. The_________ connect the ECM to the ________. 11. The _____________________ (ECM) Fig. 6.29

Function- Cell to cell communication and cell-cell contact Plant cells are perforated with ____________________, channels allowing cysotol to pass between cells. 12. _______________________ Not in text