ap bio unit 2

• Ribosomes


  the location of protein synthesis (translation). RNA is read and the code used to form a polypeptide chain
• Smooth ER


  In charge of detoxification and formation of new phospholipids
• Rough ER


  Studded with ribosomes, proteins are made here that are then transported to other parts of the cell, or to leave the cell.
• Golgi complex


  Proteins come here to be modified and tagged to be sent to other parts of the cell, or to leave the cell.
• Mitochondria


  Location of Cellular

  Respiration, forming ATP that powers cellular processes.
• Lysosomes


  Contain enzymes that break down faulty cell parts and invaders. Often described as the recycling centers of the cell.
• Vacuole


  Used for storage of water and other dissolved compounds needed by the cell. Large central vacuole in plants also used for support to hold up the cell wall.
• Chloroplasts


  Site of Photosynthesis in autotrophs. Light energy is used to create glucose,

  converting radiant energy into chemical energy.
• Which cell parts are found in both eukaryote and prokaryote cells?

  Ribosomes, cell membrane
• What does this suggest about the history of life?

  The last universal common ancestor to all life likely had ribosomes and a cell membrane, which it then passed down to all of its descendants, eventually evolving into all domains of life.
• You are studying a cell and notice that Protein A is in the wrong location. What organelles may not be functioning properly? (there are two possibilities)

  The golgi complex, or the Rough ER
• Predict what would happen if the lysosome membrane broke open. Explain your prediction.

  Lysosomes are full of enzymes designed to break down cell parts, if these enzymes were not contained (spilled out into the cell) they could destroy the cell and kill it.
• Do you think cells would do this on purpose? They do! When?

  During controlled cell death- apoptosis
• You have not watered your plant in a few days. It is droopy and floppy. What has happened on a cellular level (be specific to a particular organelle)? What will happen if you water it? Explain.

  - The central vacuole of the plant cells is designed to fill with water and push against cell walls, holding the plant upright.

  - When dehydrated, the vacuoles shrink, and are no longer pushing against cell walls, so they sag, leading to drooping plants.

  - When the plant is watered, vacuoles will fill again, push against cell walls, and the plant will stand upright again.
• Location of Krebs Cycle in mitochondria

  Folded inner membrane (matrix)
• Location of ETC in mitochondria

  Proteins involved in the ETC are embedded on folded inner membrane
• Predict the symptoms of a person whose mitochondria have 50% less folding in their inner membrane. Explain their prediction.


  - The inner membrane holds enzymes involved in the ETC. The more membrane, the more surface area there is for ATP Synthase, which generates ATP. With less membrane, there would be fewer ATP Synthase, so less ATP production. - This person would be very tired all of the time, having very little energy and not able to do physical activities - muscles require a large amount of ATP.

  - They may also have trouble thinking or concentrating, nerve cells also use a lot of ATP.
• Location of light dependent reactions in chloroplasts

  Grana
• Location of carbon fixation in chloroplasts

  Stroma
• Predict the result of doubling the number of thylakoids on glucose production in this chloroplast. Explain your prediction.

  - With twice the number of thylakoids, there would be double the surface area to conduct light dependent reactions.

  - This would likely lead to an increase in glucose production (if the enzymes in the Calvin Cycle can keep up).

  - Additional glucose would allow the plant to grow faster (more cell wall material and more energy) provided that other requirements for growth are met (sufficient nitrogen and phosphorous available).
• Mentally drop each loaf into water. Which loaf will become saturated first? Explain why.

  Cutting the loaf of bread into slices increases the surface area exposed to the water. The higher surface area to volume ratio of the sliced bread will cause it to become fully saturated sooner than the un-cut loaf.
• If the loaf were a living organism, why would it be better for that organism to be composed to many small pieces rather than one large piece?

  Living organisms must be able to quickly take in substances from the environment and get rid of waste. The smaller the organism, the higher its surface area to volume ratio is, allowing it to perform transport into and out of the cell more quickly.
• Picture a hot potato. Now picture a GIANT HOT POTATO! Which potato will cool off faster? Why? Explain in terms of SA/V ratio.

  The large potato would take a lot longer to cool off, as it has a smaller surface area to volume ratio. The best way to cool a hot potato is to open it up and cut it into pieces, increasing the surface area exposed to cool air.
• The hot potato is now a mouse, and the GIANT hot potato is now an elephant. Which organism must have a higher metabolic rate (burn more energy) to maintain its body heat? Explain why.


  - The elephant has a low SA to V ratio, so it holds onto heat, meaning it needs to spend less energy heating itself. - The mouse, being small, has a high SA to V ratio and looses heat to the environment at a higher rate - so it must burn more energy per unit mass in order to maintain its body temp.
• Draw a root hair cell. Why is its shape important to its function?

  The extended

  protrusion of the

  cell increases the

  SA to V ratio,

  allowing for faster

  uptake of water

  and minerals into

  the cell.
• Draw a gut epithelial cell. Why its shape important to its function?

  Microvilli - extensions

  of the cell membrane -

  increase the surface

  area, allowing for

  quicker absorption of

  nutrients from the

  small intestine to be

  absorbed into the

  blood stream.
• Draw a very simple plant cell with a large central vacuole. How does a vacuole increase the rate that plant cells can exchange materials with its environment?

  Vacuoles store food

  and nutrients, as

  well as wastes,

  winch can quickly

  diffuse into or out of

  the cytoplasm either

  to the environment,

  or to the vacuole.
• Draw a red blood cell. Why is the shape of the RBC important to its function?

  RBCs are flattened, with an impression in the middle. This increases the surface area of the cell, allowing for more rapid absorption of oxygen into the cell, and release of oxygen as it moves though the body tissues.
• There are three proteins embedded in the membrane. Choose a color for

  hydrophobic R groups

  and hydrophilic R groups.

  Hydrophobic

  R Groups

  would embed

  in the hydrophobic

  region between

  phospholipd lipid

  layers, while the

  hydrophilic R groups

  would be sticking out

  of the membrane,

  exposed to water.
• The fluid mosaic model states that the parts of the cell membrane continually move past one another. If the diagram above were a photo of a living cell membrane, draw a representation of that same cell if you took another photo 20 minutes later.

  Any drawing with the proteins in different positions- showing that the proteins have moved.
• How does the Fluid Mosaic nature of the cell membrane impact its ability to allow some small molecules pass through freely?

  As phospholipids are flowing around, small non-polar molecules are able to diffuse though the membrane more easily. A rigid cell membrane would be less permeable to these molecules.
• What property of the phospholipid bilayer prevents the movement of

  small polar molecules across the membrane?

  The hydrophobic portion of the bilayer prevents polar (hydrophilic) molecules from being able to come across the membrane.
• What kinds of cells have cell walls (three types), and what type of carbohydrate material is each cell wall made of?

  Plants- cellulose

  Fungus- chitin

  Bacteria- peptidoglycan
• Name 2 functions of the cell wall.

  Cell walls provide structural support for the cell. They also prevent the cell from taking on too much water via osmosis, providing pressure against the inflow of water, so that the cell does not burst in hypotonic environments.
• Plasma B cells do a lot of


  Exocytosis to move antibodies across the membrane
• Neurons do a lot of

  Exocytosis to move neurotransmitters across the membrane
• Macrophage cells do a lot of

  Endocytosis to move bacteria across the membrane
• Palisade plant cells do a lot of

  Exocytosis to move glucose across the cell membrane
• Glucose


  Requires a protein channel, it is too large to cross the

  membrane
• Na+ ions


  Requires a protein channel, while it is small, Na+ is a

  charged ion, so it will not be able to cross the hydrophobic barrier