Lecture 5.2 Flashcards
What is the endomembrane system?
It includes plasma membrane, nuclear envelope, endoplasmic reticulum (ER), Golgi apparatus and lysosomes.
How do substances get from compomnent to component in the endomembrane system?
By tiny, membrane-bound vesicles.
What is the Endoplasmic reticulum (ER) ?
A network of membranes in the cytoplasm with a large surface area
What is the rough endoplasmic reticulum (RER) ?
Has 80S (large) ribosomes that synthesize proteins and modifies them, folds them, and transports them to others regions.
What is the smooth endoplasmic reticulum (SER) ?
Lacks ribosomes and is associated with synthesis lipids and some detoxification.
What is the Golgi apparatus?
-Composed of flattened sacs (cisternae) and small vesicles.
-Receives proteins from RER and can further modify them
-Packages and sorts proteins
-And in plant cells, polysaccharides are synthesized here for the making of cell walls
Which region of the Golgi receives vesicles from ER?
The cis-region
Which region of the Golgi releases vesicles that get moved to the plasma membrane and other organelles??
The trans-region
What are lysosomes?
They contain digestive enzymes that hydrolyze macromolecules into monomers.
Where are primary lysosomes made?
In the Golgi apparatus
How does food enter the cell?
By phagocytosis
Primary lysosomes + phagosome = ?
Secondary lysosomes
Which enzymes hydrolyze the food molecules?
Hydrolytic enzymes
What are wastes ejected by?
Exocytosis
True or False? Cells are static.
False. Cells are not static and are constantly changing shape.
What are Mitochondria?
-double-membrane-bound organelles found in animals, plants, fungi, and some protists.
-contain one circular strand of DNA, 70S (i.e., small) ribosomes, and some enzymes.
What is cellular respiration?
When the energy contained in food molecules is transformed into energy-rich ATP molecules during a metabolism.
What are Chloroplasts?
-occur in plants and in photosynthetic protists (i.e., algae).
-are double-membrane-bound organelles.
-contain one circular strand of DNA, 70S (i.e., small) ribosomes, and some enzymes.
What is photosynthesis?
When chlorophyll and other pigments use light energy to make ATP molecules and sugars during a metabolism.
What is the endosymbiosis theory?
-the evolutionary origin of mitochondria & chloroplasts states that they originated when large prokaryotes engulfed, but did not digest, smaller ones (what are now known as mitochondria & chloroplasts).
-Mutual benefits permitted this symbiotic relationship to evolve into eukaryotic organelles of today.
-both the mitochondria & chloroplasts have their own. DNA and own 70S ribosomes and therefore make some proteins
What is peroxisomes ?
Single-membrane-bound organelles involved in oxidation of fatty acids, as well as detoxification of peroxides.
What do vacuoles contain?
Contain a single-membrane-bound compartment of water, dissolved substances, and digestive enzymes found in plant and algae cells.
What is the cytoskeleton?
It is a cellular part within the cytoplasm of eukaryotic cells that provide shape, strength and movement.
What are the 3 interacting types of protein fibers?
1) Microfilaments
2) Intermediate filaments
3) Microtubules
What is the role of Microfilaments?
They strengthen cellular structures & provide movement in animal cytokinesis, in cytoplasmic streaming and in pseudopod extension.
What is the role of Intermediate filaments?
They add strength to cell attachments in multicellular organisms.
What is the role for Microtubules?
They lengthen & shorten to help move organelles within the cell; push & pull chromosomes during cell division.
What is cilia?
Short, usually many present, move with a stiff power stroke.
What is flagella?
Longer, usually one or two present, movement is snake-like.
What is cilia & flagella made up of? What is their function?
Made of microtubules in a “9 + 2” pattern. Their function is to move the cell. Each one is anchored with a basal body made of microtubules in a “9 triplets” pattern.
What are centrioles?
They are “9 triplets” of microtubules (structurally identical to basal bodies), involved in the formation of the mitotic spindle—to which chromosomes attach during cell division.
What is the extracellular matrix?
It is anything external to the plasma membrane. The materials in this matrix provide protection, support, and attachment for cells in multicellular organisms.
What is the cellular matrix of plants & algae?
A cell wall made of cellulose.
What are the cell walls of fungi made up of?
Chitin.
What do cell walls do?
They provide structure, and a means for withstanding high osmotic pressure in aqueous environments.
What does the extracellular matrix consists mainly of?
Protein collagen and some different glycoproteins.
Which cells have NO cell walls?
Animal cells and animal like cells.
