Explain the Cell Theory Flashcards

The smallest unit of living matter

All organisms are made up of cells and that cells come only from preexisting cells.

A cell needs an adequate surface area large enough to allow nutrients to enter and rid itself of wastes. Small cells, not large cells, are likely to have an adequate surface area for exchanging wastes for nutrients.

Fimbriae -- hair like bristles that allow adhesion to surfaces. Pilus--enlongated hollow appendage used to transfer DNA to other cells. Flagellum -- rotating filament that pushes the cell forward. Glycocalyx -- gel like coating outside the cell wall. If compact it is called a capsul, if diffuse it is a slime layer. Inclusion bodies -- stored nutrients for later use. Nucleoid -- location of the bacterial chromosomes Ribosomes-- sites of protein synthesis. Plasma Membrane -- sheet that surrounds the cytoplasm and regulates the enterance and exit of molecules Cell Wall -- Structure that provides support and shapes the cell wall. Mesosome -- plasma membrane that folds into the cytoplasm and increases surface area.

Eukaryotic cells have a membrane covered nucleus, prokaryotic cells do not. Eukaryotic cells have endoplasmic Recticulum, Golgi appratus, Lysomes and a cytoskeleton whereas prokaryotic cells do not.

Invagination of the plasma membrane could have created the nuclear evenlope and an endomembrane system. Mitochondria and chlorlplast could have been independent prokaryotes that took up residence in a eukaryotic cell

Each organell (i.e. ER, Golgi Appratus, etc) is bound by a membrane that keeps the organelles seperated from the cytoplasm.

The nucleus contains chromatin in a semi-fluid medium called the nucleoplasm. Chromatin is a network of strands that undergoes coiling to form chromosomes. The nucleolus is a dark retion of chromatin wher a type of RNA called ribosomal RNA, (rRNA) is produced. The nuclear envelope is a double membrane that seperates the nucleus from the cytoplasm. The nuclear has nuclear pores that permits passage of ribosomal subunits and mRNA out of the nucleus and into the cytoplasm.

The nucleolus is a dark region of chromatin where rRNA is formed. rRNA joins with proteins to form the subunits of ribosomes. Ribosomes are small bodies in the cytoplasm where protein synthesis occurs.

The endomembrane system consits of the nuclear evenlope, the Endoplasmic Reticulum, the Golgi Appratus, and several types of vesicles. This system compartmentalizes the cell sto tht particular enzymatic reactions are restricted to specific regions. Vesicles transport molecules from one part of the system to another part.

Proteins are produced in the rough ER and lipids produced in the smooth ER are carried in transport vesicles to the Golgi appratus wher the are futher modified before being packaged in vesicles that leave the Golgi. The Golgi apparatus sorts proteins and packages them into vesicles that transport them to various cellular destinations.

Photosynthesis --Solar energy + CO2 + Water --yeilds-- carbohydrates + Oxygen Cellular Respiration -- carbohydrates + Oxygen -- yeilds-- CO2 + water + energy

Chloroplast-- are a type of double membrane plastid in a plant that contains multiple copies of the same DNA. The inner membrane ecloses a large space called the stroma which contains a concentratedmixture of enzymes. Chloroplast have thylakoids which are disk like sacks. A stack of thylakoids is called a grana. Mitochondria--have two membranes, the outer membrane and the inner membrane. the inner membrane is highly convoluted into cristae that projects into the matrix. the cristae increase teh surface area of the inner membrane. The matrix contain mitochondrial DNA and ribosomes. These two organells are related because they are the energy producing organelles of both plants and animals.

Actin filaments --form a dense, complex web just under the plasma membarane which is responsible for movement of the cell and its organelles. Intermediate Filaments--rope like assembley of fibrous polypeptieds which act as a support. MICROTUBULES--small hollow cylinders that help maintain the shape of the cell and also act as tracks on which organells move.

Flagellum and cilia have a 9+2 pattern of microtubules. This is nine microtubule doubletts with two cnetra microtubules. Centrols have a 9+0 pattern of micro tubules, This is nine triplets of microtubules with no central micro tubule. It is thought that the centrols give rise to the basal body which controls the flagellum and cilia.