Biology Term 3

Identify a Peripheral Protein

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Identify cholesterol molecule

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Figure 1 shows a model of how a channel protein influences the movement of a particle across a cell's plasma membrane. Figure 1. A section of a cell's plasma membrane, showing a channel protein and a concentration gradient across the membrane An investigator wants to understand whether a newly found membrane protein is involved in the membrane transport of a certain particle. Which investigation will help determine whether the new membrane protein is a channel protein involved in membrane transport?

Add more of the proteins to the plasma membrane and measure the rate of the particle movement.

Which of the following is true about the amino acids that make up a transmembrane protein?

Amino acids with nonpolar side groups are in contact with the fatty acid region of the cell membrane.

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.

The illustration shows the active transport of hydrogen ions through a membrane protein. Which of the following best predicts the effect of not having ATP available to supply energy to this process?

H+ ions will stop moving through the protein

. 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.

Which type of biological macromolecule is the main component of the plasma membrane?

Lipids

Which are example is hydrophobic in nature? 1- Oil 2- Sugar 3- Salt

Oil

The model below shows the structure of a portion of a plasma membrane in an animal cell. Which statement best explains the orientation of the phospholipid molecules in this model?

The hydrophilic phosphate groups of the phospholipid molecules are attracted to the aqueous internal and external environments.

The model below shows the structure of portion of a plasma membrane in an animal cell. Which statement best explains the orientation of phospholipid molecules in this model?

The hydrophilic phosphate groups of the phospholipid molecules are attracted to the aqueous internal and external environments.

What is the "big idea" of the fluid mosaic model of plasma membrane?

a plasma membrane is a MOSAIC of components that move FREELY and FLUIDLY.

A model of the plasma membrane showing several biological molecules, including a transmembrane protein, is shown in figure 1 ( Figure 1.Phospholipid bilayer with transmembrane protein). Which statement best explains why correct protein folding is critical in the transmembrane protein shown above?

interactions of the hydrophobic and hydrophilic amino acids helps to anchor to the protein in the membrane.

Which of the following describes how phospholipid regions are positioned in the cell membrane?

Hydrophilic phosphate regions are positioned towards aqueous environment.

Which of the following best describes the numbered areas?

Areas 1 and 3 are polar, since the membrane molecules are aligned with water molecules.

Which of the following best describes how high levels of cholesterol affect the cell membrane at certain temperatures?

At low temperatures, high amounts of cholesterol increase the fluidity of cell membrane.