Chp. 3 - Part 2, The Cytoplasm

Question 1

cytoplasm

Answer 1

• “cell forming material” - cellular material between the PM and the nucleus
• the site of most cellular activities
• consists of: cytosol, inclusions, and organelles

Question 2

cytosol

Answer 2

viscous, semitransparent fluid to which the other cytoplasmic elements are suspended.
mix of water and dissolved proteins, salts, sugars, and other solutes

Question 3

inclusions

Answer 3

are insoluble molecules including glycogen, granules, pigments, lipids, vacuoles, and crystals that are in the cytoplasm

Question 4

organelles

Answer 4

metabolic machinery of the cell.

Each organelle carries out a specific function

Question 5

Mitochondria

Answer 5

• Energy house
• Thread-like membraneous organelle with an inner membrane (cristae) that folds and is shelf-like and a smooth outer membrane
• Have their own DRA, RNA, and ribosomes and can reproduce themselves (binary fission) - probably evolved from bacteria
• Passed in humans through female

Question 6

Ribosomes

Answer 6

• Site of protein synthesis
• granules made of proteins and ribosomal RNAs
• Free or membrane-bond (and can switch between the two)
• have a top and a bottom

Question 7

free ribosomes

Answer 7

float freely in cytosol

make soluble proteins that function in cytosol and those imported into mitochondria/other organelles

Question 8

membrane-bound ribosomes

Answer 8

ribosomes attached to the rough endoplasmic reticulum

synthesize proteins to be part of PM, inside lysosomes or for export

Question 9

Endoplasmic Reticulum (ER)

Answer 9

• system of interconnected membranous channels
• continuous with the outer membrane of the nucleus
• contains half of a cell’s membranes
• Rough & Smooth

Question 10

Rough ER (RER)

Answer 10

• studded with ribosomes that synthesize proteins mean for PM/export
• once ribosomes make their way through membranes of Rough ER, goes to Golgi apparatus for further processing

Question 11

Smooth ER (SER)

Answer 11

-continuos with Rough ER and consists of tubules arranged in looping network
-site of lipid and steroid (cholesterol) synthesis
-lipid and carbohydrate metabolism
-drug detoxification
-in skeletal and cardiac cells, stores and releases calcium (other than this most body cells have very little smooth ER
^Other than these most body cells have very little, if any smooth ER

Question 12

Golgi Apparatus

Answer 12

• stacked and flattened membranous sacs with tiny membranous vesicles surrounding (the stacks are not connected).
• This is the packaging and processing center of the cell for proteins
• modifies, concentrates, and packages proteins and lipids from rough ER into 3 different types of ‘final transport vesicles’ (pathway A, B, or C)

Question 13

Pathway A final transport

Answer 13

secretory vesicles/granules containing proteins destined for export migrate to PM and discharge their content from cell via exocytosis
aka - exit pathway

Question 14

Pathway B Final Transport

Answer 14

vesicles containing lipids & transmembrane proteins destined for PM or other membranous organelles
aka - membrane pathway

Question 15

Pathway C Final Transport

Answer 15

vesicles containing digestive enzymes are packaged into membranous lysosomes that remain in the cell (where they wait until cell needs these enzymes)
aka - storage pathway

Question 16

Peroxisomes

Answer 16

• like smaller lysosomes, these are membranous sacs containing enzymes, most importantly oxidases and catalases
• these help detoxify substances or neutralize them, like free radicals (toxic, highly reactive byproducts of cellular metabolism)
• also play a role in energy metabolism by breaking down and synthesizing fatty acids
• heavily present in macrophages (type of white blood cell)

Question 17

oxidases + catalases

Answer 17

• enzymes within peroxisomes.

- oxidases uses O2 to convert free radicals to hydrogen peroxide, which the catalases then coverts to water

Question 18

Lysosome

Answer 18

• disposal site of the cell
• spherical membranous organelles containing activated digestive enzymes
• lysosome membrane contains H+ pumps that gather hydrogen ions from cytosol maintaining the organelles acidic pH (good for breaking down wastes)
• Functions:
  1. digest harmful particules brought in via endocytosis
  2. degrade dead/non functional cells / organelles
  3. glycogen breakdown and relese
  4. breaking down bone to release Ca+ ions in blood

Question 19

Autolysis

Answer 19

• process of cell eating itself (esp dead cells)

- start with lysosome

Question 20

Endomembrane system

Answer 20

membranous organelles (ER, golgi, secretory vescioles, lysosomes, peroxisomes) + nuclear membrane + PM that work together to produce, degrade, store, and export biological molecules and degrade harmful substances
^The system is either structurally connected or arise via forming/fusing transport vesicles with a membrane

Question 21

Cytoskeleton

Answer 21

-AKA Cell skeleton
-network of rods running through cytosol that link rods to other cell structures
3 Types:
1. microfilaments
2. intermediate filaments
3. microtubules

Question 22

microfilaments

Answer 22

• smallest element of cytoskeleton
• semi-flexible thin strands of the actin protein
• The dense web of these in a cell is the terminal web, which attaches to inside side of PM strengthening cell surface, resists compression, and transmits force during cellular movement

Question 23

intermediate filaments

Answer 23

• the middle-sized element of cytoskeleton
• tough, insoluble rope-like, made of the tetramer (4) fibrils
• most stable and permanent of the cytoskeleton elements and have high tensile strength
• attach to desmosomes acting like internal guy-wires resisting pulling forces on the cell

Question 24

microtubles

Answer 24

• the largest element of cytoskeleton
• hollow tubes made of tubulin (spherical protein subunits)
• come from the centrosome
• determine overall shape and distribution of organelles in a cell

Question 25

centrosome

Answer 25

- AKA cell center - region near the nucleus in cytoplasm - microtuble organizing center - contains centrioles - organizes the mitotic spindle during cell division

Question 26

Centrioles

Answer 26

- barrel shaped organelles oriented at right angles that contain 9 triplets of microtubules in a many-pointed hollow start shape. - found in the centrosome - involved in development of spindle fibers during cell division

Question 27

Cilia

Answer 27

- whiplike, cellular extensions typically in large numbers - they help move what's on a cell surface in a single direction (like mucus in respiratory tract) - having sweeping motion -power stroke and recovery stroke - form from centrioles (basal bodies)

Question 28

flagella

Answer 28

- propels a cell - only the spem cells has this - made from centrioles (basal bodies)

Question 29

basal bodies

Answer 29

the centrioles that form the bases of cilia and flaggela. They have a 9+2 , nine doublets encircling a single pair pattern of microtubles

Question 30

microvilli

Answer 30

- fingerlike projections over cell that increase the surface area, which is helpful where absorption is needed (kidney and intestines) - made of a core of bundled actin (a protein) filaments that extend into the terminal web of cell

Question 31

proteasome

Answer 31

non-membranous organelles made of multiple enzymes that remove faulty/unneeded proteins

Question 32

Tay-sachs disease

Answer 32

- an inherited disease caused by the lack of a certain enzyme within lysosomes, causing them to swell with undigested lipids which interfere with nerve functioning. - symptoms include mental retardation , seizure, blindness, and death before age 5 typically

Question 33

lipid rafts

Answer 33

dynamic assemblies of proteins and lipids that float freely within the liquid-disordered bilayer of cellular membranes; serve as organizing house for cell signaling