Lab 2

Question 1

Cilla

Answer 1

• Cilia consist of a group of microtubules enclosed by the cell membrane.
• membrane bound eukaryote cells
• Microtubules are hollow tubes made of a protein called tubulin.
• In addition to forming cilia, microtubules play an important role in a cell’s cytoskeleton to form a rigid structure to maintain cell shape and to act as a framework to move organelles around inside the cell.

Question 2

two kinds of cilia:

Answer 2

• primary and motile.
• Primary do not move
  – lacks the center microtubule doublet.
• Motile move.
  – Each motile cilia consists of pairs of microtubules arranged in a “9+2” pattern

– 9 pairs of tubules spaced around the outside (periphery) of the cell and a pair of 2 single tubules in the center.

Question 3

Researchers have observed in human studies that smoking can have a variety of effects on cilia:

Answer 3

• change in cilia beat frequency

-impairment of cilia movement

-reduction in cilia length

• two-fold effect: it paralyzes and damages the air way cilia preventing them from sweeping mucus, and over time destroys ciliated cells and encourages the replication of mucus-producing cells.

Question 4

dynein, “molecular motor ”

Answer 4

• provides the force needed to move the microtubules, and that action in turn moves the cilium.
• is attached to one microtubule in each pair of microtubules that makes up the outer ring
• it can change its shape when it binds to ATP.
• shape change protein undergoes allows it to bind to the second microtubule in the pair, pull on it, and then release.
• “row boat”
• pull and release, causing the cilia to bend.

Requires:
1. thousands of molecules of ATP every second
2. a way to coordinate each pair of microtubules, so that they all beat in the same direction at the same time.

Question 5

locations of motile cilla and their functions

Answer 5

• Motile cilia in unicellular organisms aides in cell movement and/ or feeding via moving food particles to an oral cavity.
• Motile cilia are also found in reproductive organs: they line the fallopian tubes and help sweep the egg towards the uterus.
• In humans, cilia line the respiratory tract and act to sweep mucus out of the lungs.

Question 6

Tetrahymena

Answer 6

• are single celled protists
• the basic structure of cilia has been conserved in eukaryotic evolution
• no mouth = oral cavity
• food becomes enclosed in membrane-bound vacuole

Question 7

phagocytosis,

Answer 7

• is the process wherein food and other particles are ingested.

Process:
1. triggered by the presence of food and particles that specialized cilia have sensed in the environment and moved towards the oral cavity (“mouth”).

2. portion of the cell membrane pinches off around food particle, creating a membrane bound vacuole
3. food vacuole formed, it’s transported to a lysosome in the cytoplasm.
4. food vacuole fuses with the lysosome, where enzymes will break down the food materials.

Question 8

The environmental impacts of the fast fashion industry range from:

Answer 8

• excessive water usage (it is estimated that the amount of water used to make a single cotton t-shirt is the same as one person would drink in 2.5 years!!)
• synthetic fabrics that leach microplastics into our waterways
• chemical pollution of our waterways from the use of synthetic dyes
• increase in greenhouse gas emissions
• textile waste piling up in landfills and many more.

Question 9

Effects of dye in aquatic environments

Answer 9

• coloured wastewater blocks penetration of light
• Many of dyes are toxic or carcinogenic, even at low concentrations
• very difficult to remove even when there are treatment facilities.

Question 10

Challenges with using natural dyes on the mass scale

Answer 10

• volume needed to meet the demand may not be achieved using dyes from natural sources
• many natural dyes require the addition of harmful chemicals to fix the dye to the fabric (use of mordants)
• the quality, consistency and range of colours achieved using natural dyes does not compare to synthetic dyes.

Question 11

Cell Membranes

Answer 11

• function to separate the contents of the cell from the external environment and organize specific chemicals and reactions into specific compartments ( i.e., organelles) within the cell.
• membrane is a fluid bilayer of phospholipids and proteins, both the phospholipids and the proteins are vital to the function of the cell membrane.
• phospholipid bilayer is impermeable to most polar molecules because of its hydrophobic (nonpolar) interior formed by the lipid tails of phospholipids.
• prevents the water-soluble contents of the cell from escaping.

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Question 12

betacyanin

Answer 12

• red pigment contained in Beet cells
• located in the large central vacuole of the cell.
• central vacuole is a large storage compartment surrounded by a membrane called the tonoplast and is in the cytosol of the cell.
• cell itself is surrounded by another membrane, the cell membrane
• If both membranes remain intact, the betacyanin will remain inside the vacuole within the cell.
• However, if these membranes are damaged, the betacyanin will leak out.

Question 13

Hydrophilic molecules

Answer 13

• are impeded by the fatty acid “tails” of the phospholipids in the center of the membrane and diffuse more slowly.

Question 14

Hydrophobic molecules

Answer 14

• are attracted to this nonpolar zone and may disrupt normal lipid packing , resulting in damage to the membrane.

Question 15

temperature effects on membranes

Answer 15

• Higher temperatures increase kinetic energy which increases the fluidity of the lipids in the membrane.
  –> can damage membrane
• Proteins are also damaged by higher temperatures, leading to further damage to the integrity of the cell membrane.