BIOL 1120 - LAB 3

Question 1

what is a cell membrane?

Answer 1

• boundaries of the cell
• controls the passage of the materials into and out of the cells

Question 2

what is a nucleus?

Answer 2

• large organelle IN the cell
• contains thread-like matter called chromatin which contains DNA and protein

Question 3

what is a cytoplasm?

Answer 3

• all contents of a cell except the nucleus
• cytosol is the liquid component of cytoplasm that surrounds the organelles

Question 4

what is a nucleolus?

Answer 4

• dark mass found in the nucleus
• where ribosomes are produced

Question 5

what is the nuclear membrane/envelope?

Answer 5

• composed of a double layer membrane that are held together at nuclear pores
• separates the contents of the nucleus from the rest of the cell

Question 6

what are ribosomes?

Answer 6

• small, dark granules composed of protein and RNA
• found free in the cytosol
• also found on the surface of the rough endoplasmic reticulum
• responsible for interpreting the genetic code and synthesizing polypeptides (amino acid protein chain)

Question 7

what is the ROUGH endoplasmic reticulum?

Answer 7

• network of flattened sacs that are connected to each other
• sacs are called CISTERNAE
• called “rough” b/c it is covered in ribosomes
• make proteins and produce cell membranes

Question 8

what is the SMOOTH endoplasmic reticulum

Answer 8

• network of linked membrane-enclosed sacs
• differs from rough ER in that the cisternae are more tubular and branch more extensively
• lacks ribosomes (thats why called “smooth”)
• lipid synthesis
• stores calcium ions
• involved in the detoxification of drugs

Question 9

what is the golgi apparatus?

Answer 9

• synthesizes carbohydrates and adds these to proteins that have been synthesized in rough ER
• packages these modified proteins inside golgi vesicles

Question 10

what is the mitochondria?

Answer 10

• have a double layer membrane
• inner membrane contains folds called cristae
• generate most of the chemical energy needed to power the cells biochemical reactions
• reproduce independently of the cell and live for 10 days

Question 11

what is a cristae?

Answer 11

• folds in the inner membrane of mitochondria -space b/w the cristae is called the matrix
• enzymes on the cristae synthesize ATP from energy extracted from organic compounds
• folds increase surface area
• increased surface area allows mitochondria to produce more energy at a faster rate

Question 12

what are lysosomes?

Answer 12

• packages of enzymes (proteins) enclosed in a single unit membrane and can vary in shape
• break down different molecules
• digest worn-out organelles
• involved in programmed cell death
• in liver cells, break down glycogen

Question 13

what are exocytotic vesicles?

Answer 13

• type of vesicle involved in vesicular transport
• releasing waste and large molecules from the cytoplasm to the outside of the cell

Question 14

what is endocytosis?

Answer 14

• type of vesicular transport that moves substances INTO the cell
• cells take in substances from outside of cell by engulfing then in a vesicle

Question 15

what is an endocytotic vesicle?

Answer 15

• formed during endocytosis
• cells ingest fluid, molecules, and particles by endocytosis and forms vesicles that moves them into the cell

Question 16

what is glycogen?

Answer 16

• stored form of glucose
• made up of connected glucose molecules
• glucose is our body’s main source of energy

Question 17

what is the brush border?

Answer 17

• inner edge of the tissue
• dense covering of microvilli
• specialize in absorption

Question 18

what are microvilli?

Answer 18

• extensions of the plasma membrane of cells
• contains protein filaments, made of actin, attaching from the tip to the base
• increase the surface area of the cell membrane

Question 19

what are goblet cells?

Answer 19

• secretes materials necessary for digestive processes
• found in small intestines
• produce mucin that serves for digestion
• create a protective mucus layer and lubricates the surface of intestines

Question 20

what are desmosomes?

Answer 20

• pin adjacent cells together, ensuring that cells in organs and tissues that stretch (like skin and cardiac muscle), remain connected in an unbroken sheet
• found in epithelial tissues ex. stratified squamous epithelium

Question 21

what are cilia?

Answer 21

• hair-like processes found on the surface of some animal cells
• found on cells in the respiratory tract and uterine tubes
• function to move mucus

Question 22

what are intercalated discs?

Answer 22

• responsible for connecting cardiac muscles, allowing them to contract in unison as a single functional unit

Question 23

what are gap junctions?

Answer 23

• joining cells that allow material to pass directly from one cell to the next, since they contain pores that allow transit
• in cardiac muscles, they are important for the transmission of the electrical signals that provide a coordinated heart beat

Question 24

what is an extracellular matrix?

Answer 24

• helps cells attach to, and communicate with, nearby cells
  plays an important role in cell growth, cell movement, and other cell functions
• involved in repairing damaged tissue

Question 25

what is cytoskeleton?

Answer 25

• collection of filaments and tubules that provide internal support and movement of the cell
• composed of microfilaments, intermediate filaments, and microtubules

Question 26

what is flagella?

Answer 26

• single, long, whip-like structures
• they whip around and sometimes twirl, pushing the cell along
• produced from the cytoskeleton
• energy to move them is provided by mitochondria

Question 27

what is mitotic spindle?

Answer 27

• structure that forms during cell division and separates duplicated chromosomes
• in other words, used to direct movement of the chromosomes during cell division

Question 28

what are centrioles?

Answer 28

• help to control and regulate activity of the cytoskeleton
• spindle formation during cell division
• made of microtubules
• short, cylindrical assemblies of microtubules
• help determine the locations of the nucleus and other organelles within the cell

Question 29

what are asters?

Answer 29

• cellular structure shaped like a star
• formed around each centrosome during mitosis in animal cells