Unit 2 questions from previous test

A major distinction between prokaryotes and eukaryotes is the presence of membrane-bound organelles in eukaryotes. Describe the structure and function of TWO eukaryotic membrane-bound organelles other than the nucleus.

1. mitochondria: a organelle that has a double membrane with infolding of the inner membrane that is responsible for the preduction of ATP 2. Chloroplasts: a organelle that has a double membrane with flattened sacs called thylakoids that has the responsibility of photosynthesis or light absorption

Aquaporins are channel proteins that facilitate the transport of water across the cell membrane. One group of researchers hypothesizes that without functional aquaporins, no water will be able to enter the cell. A different group proposes an alternative hypothesis, stating that even with nonfunctional aquaporins, a small amount of water will still cross the cell membrane. An experiment is set up in which plant cells with mutated (nonfunctional) aquaporins and plant cells with normally functioning aquaporins are both placed in distilled water. Which of the following data would support the alternative hypothesis?

Cells with mutated aquaporins exhibit moderate turgor pressure and are hypertonic.

All eukaryotic cells contain at least one Golgi complex, typically located in the cytoplasm and near the endoplasmic reticulum. Which of the following best describes a process that occurs within the Golgi complex?

Enzymatic modification of newly synthesized integral membrane proteins

Plant cell walls are composed of cellulose, while fungal cell walls are composed of chitin. A group of scientists hypothesize that this difference means the cell wall has largely different functions in plant cells and fungal cells. Alternatively, another group of scientists hypothesize that despite their biochemical differences, plant and fungal cell walls serve similar functions. Which of the following observations would best support the alternative hypothesis described above?

In both plant cells and fungal cells, the cell wall surrounds the outside of the cell membrane.

If ATP breakdown (hydrolysis) is inhibited, which of the following types of movement across cell membranes is also inhibited?

Passage of a solute against its concentration gradient

Which of the following components of the cell membrane is responsible for active transport?

Protein

Intravenous (IV) solutions administered to patients are normally isotonic. Which of the following is most likely if an IV of distilled water is administered to a patient?

The cells that are exposed to hypotonic solutions will expand as water moves osmotically into the cells from the blood.

Which statement best describes the effect on water transport across the cell membrane if the aquaporin in the figure ceases to function?

Water molecules will still be able to move across the cell membrane but at a slower rate.

This group of questions refers to the following groups of biological compounds. (A) Proteins (B) Carbohydrates (C) Nucleic acids (D) Lipids (E) Steroids Synthesized at the ribosome

a) proteins

When a substance moves across the plasma membrane along a concentration gradient at a rate faster than would be expected by simple diffusion alone but without the expenditure of metabolic energy, the process is best described as

facillitated diffusion

A cell is treated with a drug that prevents the formation of new lysosomes. The cell continues to transcribe the genes that code for the hydrolytic enzymes that are normally found in lysosomes and continues to translate the mRNAs for those proteins on membrane-bound ribosomes. The hydrolytic enzymes are most likely to accumulate in which of the following cellular structures?

golgi complex

Site of modification and packaging of proteins and lipids prior to export from the cell

golgi complex

facilitated diffusion allows what type of molecules and ions to pass through the membrandes

hydrophilic

Describe the characteristics of the Ca2+ ions and the plasma membrane of the kidney cell that prevent the Ca2+ions from moving from Region II into the kidney cell without the channel labeled CC.

ions are charged/hydrophilic and the interior of the membrane is nonpolar/hydrophobic

Contains hydrolytic enzymes associated with the intracellular digestion of macromolecules

lysosomes

passive transport

net movement of molecules from high concentration to low concentration without the use of metabolic energy such as atp

active transport

requires the direct input of energy to move molecules from low concentration to high concentration

facilitated diffusion is a type of passive transport that happens where

through a non-specific or specific transporter

diffusion is a type of passive transport that happens where

through the lipid bilayer