Chapter 3

Question 1

• Responsible for ATP generation for cellular activities
• Density of this organelle reflects the cell’s energy requirement (busy cells have hundreds while relatively inactive cells have a few)
• Contain their own DNA, RNA and ribosomes and can reproduce themselves
• When ATP increases, the organelle synthesizes more cristae or or simply pinch in half (fission) to increase their numbers

Answer 1

Mitochondria

Question 2

• Sites of protein synthesis
• Composed of proteins and a variety of RNAs
• two types: Free and Membrane-bound

Answer 2

Ribosomes

Question 3

• Extensive system of interconnected tubes and parallel sacs called cisterns
• Organelle is continuous with the outer nuclear membrane and accounts for able half of the cell’s membranes
• 2 varieties

Answer 3

Endoplasmic Reticulum

Question 4

• External surface of the organelle is studded with ribosomes
• Its ribosomes manufacture all proteins secreted from cells
• Well developed in most secretory cells, antibody-producing immune cells and liver cells
• Cell’s “membrane factory” where integral proteins and phospholipids that form part of all cellular membranes are manufacture

Answer 4

Rough Endoplasmic Reticulum

Question 5

• Consists of tubules arranged in a looping network
• No ribosomes present is a defining feature
• Its enzymes do not play a role in protein synthesis
• Metabolizes lipids, synthesize cholesterol, and phospholipids, and synthesize the lipid components of lipoproteins
• synthesize steroid based hormones such as sex hormones
• Detoxify drugs, certain pesticides and cancer causing chemicals
• Break down stored glycogen to form free glucose
• Store calcium ions in most cell types

Answer 5

Smooth Endoplasmic Reticulum

Question 6

• Membranous system close to the cell nucleus that packages protein secretions for export, packages enzymes into lysosomes for cellular use, and modifies proteins destined to become part of cellular membranes
• Traffic director for cellular proteins

Answer 6

Golgi Apparatus

Question 7

• Membranous sacs in cytoplasm containing powerful oxidase enzymes that use molecular oxygen to detoxify harmful or toxic substances, such as free radicals
• Numerous in the liver and kidney cells, very active in detoxification

Answer 7

Peroxisomes

Question 8

• Organelles that originate from the Golgi apparatus and contain strong digestive enzymes
• Abundant in phagocytes
• Can digest almost all kinds of biological molecules
• When they rupture, the cell digests itself (autolysis)

Answer 8

Lysosomes

Question 9

• System of organelles that work to produce, degrade, store and export biological molecules
• Degrade potentially harmful substances
• Includes ER, Golgi apparatus, secretory vesicles and lysosomes

Answer 9

Endomembrane system

Question 10

• Cell skeleton
• Elaborate network of rods running through the cytosol and hundreds of accessory proteins that link these rods to other cell structures
• Acts as the cell’s bones, muscles and ligaments by supporting cellular structures and providing the machinery to generate various cell movements
• 3 types of rods: microfilaments, intermediate filaments, and microtubules

Answer 10

Cytoskeleton

Question 11

• Semiflexible strands of the protein “actin”

* Involved in cell motility or changes the cell shape

Answer 11

Microfilaments

Question 12

• Tough, insoluble protein fibers constructed like woven ropes composed of tetramer fibrils
• Most stable and permanent of the cytoskeletal elements and strongly resist tension

Answer 12

Intermediate Filaments

Question 13

• Hollow tubes made of spherical protein subunits called tubulin
• Grow out from the centrosome, disassemble and then reassemble at the same or different sites
• They determine the overall shape of the cell as well as the distribution of cellular organelles
• Mitochondria, lysosomes and secretory cesicles attach to the __________ like ornaments and motor proteins continually move and reposition the organelles along the _________

Answer 13

Microtubules

Question 14

• Region near the nucleus that contains paired organelles called centrioles
• Acts as the microtubule organizing center
• Best known for generating microtubules and organizing the mitotic spindle in cell division

Answer 14

Centrosome

Question 15

• Minute body found in pairs near the nucleus of the cell, active in cell division
• Consists of a pinwheel array of nine triplets of microtubules, each connected to the next by nontubulin proteins and arranged to form a hollow tube
• Form the bases of cilia and flagella

Answer 15

Centrioles