The cell is the lowest level of structure that is capable of performing all the activities of life. The first cells- cork, Robert ___________ in Anton van ________________ - first saw single- celled organisms in pond water and observed cells in blood and sperm. In 1839, Matthais Schleiden and Theodor Schwann –The ________________- all living things consist of cells. A cell theory extension - all ______ come from other _____. Cell Structure and Function Chapter 4 Early Discoveries

Smallest unit of ____ Can survive _____________ or has potential to do so Is highly organized for __________ Senses and responds to ____________ Has potential to ________________ Cell

Prokaryotic vs eukaryotic cells 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. Structure of Cells

Main component of cell ____________ Gives the membrane its _____ properties Two layers of ______________ Lipid Bilayer Fluid Mosaic Model Membrane is a mosaic of –_______________ –______________ –Sterols –_______________

Membrane Proteins __________proteins _________ proteins Recognition proteins ___________ proteins Why Are Cells So Small? Surface-to-volume ratio A bigger cell = less _________________ per unit volume Above a certain size, material cannot be moved in or out of cell _____________

Diameter (cm): Surface area (cm 2 ): Volume (cm 3 ): Surface- to-volume ratio:13.17:16.04:1 3.99:1 Fig. 4.5, p. 54

___________ microscope -minimum resolution is - _ _______ ( the size of a small bacterium) For higher resolution- -__________ microscope -Transmission Electron Microscope -Scanning Electron Microscope Microscopy

Fig. 7.7 Animal cell Animal cells lack: _____________ ______________

Fig. 7.8 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 nucleus

___________ (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 ______________

_____________- contain _______ (from nucleolus) and __________. composed of two subunits carry out __________ synthesis. 2. Ribosomes build a cell’s proteins Fig. 7.10

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.)

The _____________________- includes the nuclear envelope endoplasmic reticulum Golgi apparatus lysosomes vacuoles plasma membrane. Where are the membranes produced?? The _____

Two regions of ER that differ in structure and function. –_______ ER ribosomes attached to the outside Packages proteins into ____________________ –__________ ER lacks _____________ Function: synthesize lipids, including oils, phospholipids, and steroids –Also _________________ drugs and poisons Fig The endoplasmic reticulum

Function: _________, ____, and ______ cell products Many transport vesicles from the ER travel to the ________ __________________ for modification of their contents. 4. The Golgi apparatus Cis face “receiving” Trans face “shipping” ____ face _______ vesicles from ER; ______ face ships vesicles out

a membrane-bounded sac of ________ enzymes functions -digest ________________ (proteins, fats, polysaccharides, and nucleic acids). Low pH (5.0) 5. Lysosomes Fig. 7.13a massive leakage from lysosomes can destroy an cell by __________ Nucleus Lysosome

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

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 another organelle 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…., 6. Vacuoles

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. ___________, 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. Mitochondria and chloroplasts Chloroplast Mitochondria

Mitochondria and chloroplasts- – Are _____ part of the endomembrane system. 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.

Endoplasmic reticulum Ribosomes Nucleus Review Nucleolus DNA Produce mRNA Produce rRNA (for ribosomes) Protein synthesis Produce membranes FUNCTION

Golgi Function Finishes, sorts, and ships _____________ Lysosome Nucleus digest -__________ Vacuole Food vacuole Central vacuole (plants) Transport food to lysosome Give plants rigidity Chloroplast Mitochondria Produce ATP for energy Capture light for energy (only chloroplasts)

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 Not part of __________- system

The ____________ is a network of _______ extending throughout the cytoplasm. ________: –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. 7.20

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

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

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 extracellular matrix (ECM)

Function- Cell to cell communication and cell-cell contact Plant cells are perforated with ______________, channels allowing cysotol to pass between cells. 12. ____________________ Fig inset Animal have 3 main types of intercellular links:

__________________ and Eubacteria DNA is NOT enclosed in ____________ Generally the smallest, ___________ cells No _______________ Prokaryotic Cells

Prokaryotic Structure DNA pilus flagellum cytoplasm with ribosomes capsule cell wall plasma membrane