Biology- Chapter 5 Structure and Function of Plasma Membrane

Which statements are properties of protein‑facilitated active transport? -Substances pass through the plasma membrane following a concentration gradient. -Lipid‑soluble substances diffuse through the plasma membrane. -The cell spends energy to form vesicles to transport substances across the plasma membrane. -The cell spends energy to move substances through a protein across the plasma membrane. -Substances move from an area of lower concentration to an area of higher concentration.

-The cell spends energy to move substances through a protein across the plasma membrane. -Substances move from an area of lower concentration to an area of higher concentration.

Select the descriptions that apply to the sodium‑potassium pump. -Sodium ions and potassium ions move into and out of the plasma membrane by osmosis. -The concentration gradient of the ions determines the direction of movement through the pump. -The pump helps to maintain the concentration of sodium and potassium ions in living cells. -The pump is an active mechanism for transporting ions through the plasma membrane.

-The pump helps to maintain the concentration of sodium and potassium ions in living cells. -The pump is an active mechanism for transporting ions through the plasma membrane

Which situations involve a cell using endocytosis? A cell wraps a portion of its membrane around a droplet of nutrient‑rich water and brings the droplet inside the cell. Specific molecules bind to cell membrane proteins, triggering the membrane to fold around the molecules and bring them into the cell. A free‑living single‑celled organism engulfs a smaller single celled organism and uses the smaller organism as a food source. Digestive enzymes are disgorged into the small intestine through the cell membrane of the cell in which they were produced. Water moves across a cell membrane and into a cell through specialized protein tunnels in response to a concentration gradient.

A cell wraps a portion of its membrane around a droplet of nutrient‑rich water and brings the droplet inside the cell. Specific molecules bind to cell membrane proteins, triggering the membrane to fold around the molecules and bring them into the cell. A free‑living single‑celled organism engulfs a smaller single celled organism and uses the smaller organism as a food source.

Transport proteins allow the movement of ions and small molecules across plasma membranes. Identify the type of transport protein from each example as uniporter, symporter, or antiporter.

A protein moves one Cl−Cl− out of the cell and one HCO−3HCO3− into the cell.- ANTIPORTER A protein allows glucose to flow into a cell down its concentration gradient.-UNIPORTER A protein moves one H+H+ ion and one K+K+ ion out of the cell.-SYMPORTER

Exocytosis is one of the processes living organisms use to move molecules. Choose all the examples of exocytosis. Urine leaves a mouse's bladder and soaks into the soil. A single‑celled eukaryotic organism excretes digestive waste into the surrounding water. Oxygen moves out of a red blood cell through the cell membrane. A nerve cell releases peptides used as messengers into the extracellular space. Pancreatic cells release digestive enzymes into the small intestine.

A single‑celled eukaryotic organism excretes digestive waste into the surrounding water. A nerve cell releases peptides used as messengers into the extracellular space. Pancreatic cells release digestive enzymes into the small intestine.

Label the general function of each membrane protein. Protein A is a ______ protein. Protein B is a ______ protein. Protein C is a ______ protein.

A-structural B-communication C-transport

Which statements describe examples of facilitated diffusion? -A neuron moves sodium ions out of the cell against their concentration gradient using a membrane pump and cellular energy. -An inner ear hair cell allows potassium ions to flow down their concentration gradient after sound waves stimulate a membrane protein. -An erythrocyte low on glucose replenishes its supply using a membrane protein to transport glucose down its concentration gradient. -A bacterium takes in nitrogen gas directly through its plasma membrane from the atmosphere. -A neuron allows sodium ions to enter the cell down their concentration gradient using a membrane channel. -An epithelial cell absorbs amino acids against their concentration gradient using a membrane pump and the energy of another concentration gradient.

An inner ear hair cell allows potassium ions to flow down their concentration gradient after sound waves stimulate a membrane protein. An erythrocyte low on glucose replenishes its supply using a membrane protein to transport glucose down its concentration gradient. A neuron allows sodium ions to enter the cell down their concentration gradient using a membrane channel.

Which statement describes the fluid mosaic model? -an explanation of how proteins embedded within the plasma membrane aid in cell functioning -the gel‑like extracellular mix of proteins, polysaccharides, and other substances within tissues -all the liquid and solid components within a cell's interior, excluding the nucleus -a phospholipid bilayer with various molecules embedded within and floating between the layers

Answer: a phospholipid bilayer with various molecules embedded within and floating between the layers

Match each description to the correct membrane protein. Carrier protein and Channel protein

Carrier protein: A passage that is open only on one side of the membrane at a time and binds the molecule or ion being transported Channel protein: a passage the directly links the intercellular and extracellular fluids and creates a water-filled pore.

Phospholipids are molecules that have two regions, the head and the tail, with distinct chemical properties. Classify the descriptions as characteristics of the heads or tails of phospholipids.

Heads: Hydrophilic, Polar Tails: Do not mix with water, hydro-carbon rich

Integral membrane proteins have different characteristics and functions than peripheral membrane proteins. Identify the statements that are properties of integral membrane proteins and those that are properties of peripheral membrane proteins.

Integral membrane proteins: Can extend through the cell membrane, can move sideways in the hydrophobic part of the membrane, acts as tunnels through the cell membrane Peripheral membrane proteins: attach the cell membrane surface

Identify these substances as those that can easily move through the lipid bilayer of a plasma membrane and those that are repelled by the lipid bilayer and, therefore, need help from a protein to cross the plasma membrane

Move easily through the lipid bilayer of the plasma membrane Oxygen Need help from a protein to cross the membrane because they are repelled by the lipid bilayer NaCl Ca ions amino acids C6H12O6

Match the descriptions to the appropriate type of transport.

Passive transport: - doesn't require energy -moves substances down the concentration gradient Active transport -requires ATP (energy) -moves substances against the concentration gradient

Two forms of endocytosis are pinocytosis and phagocytosis. Each statement is a characteristic of either pinocytosis or phagocytosis. Match each description to the appropriate category. Pinocytosis and Phagocytosis

Pinocytosis: aka "cellular drinking" tiny vesicles are formed Phagocytosis: Large particles are engulfed Large particles are formed psuedopodia are used

Sort the descriptions into properties that describe either saturated phospholipids or unsaturated phospholipids.

Saturated phospholipids -straight fatty acid tails -fatty acid tails are packed tightly together -no double bonds in the fatty acid carbon chains -makes the membrane rigid at low temperatures Unsaturated phospholipids -bent tails -space between phospholipids -contains double bonds in the fatty acid carbon chains -allows membrane to move ok at low temperatures

A cell uses many methods to transport solutes across the plasma membrane. Classify the descriptions as either simple diffusion, facilitated diffusion, active transport, or bulk transport.

Simple diffusion: directly through the cell membrane Facilitated diffusion: down the concentration gradient Active transport: against the concentration gradient Bulk transport: movement of transport vesicles out of cell

Membrane proteins are a class of proteins that are embedded within or associated with the plasma membrane of a cell or organelle. Membrane proteins provide a variety of functions necessary for cellular survival. Classify each example as a structural, transport, communication, or recognition protein.

Structure: peripheral membrane Transport: aquaporin Communication: membrane receptor Recognition: pair of liver cells

Match each of the characteristics to the part of the lipid bilayer that has that property

Tails: hydrophobic, Fatty acid chains, repelled by polar molecules Heads: hydrophilic, contains phosphate.

Select the statements that accurately describe endocytosis. -The cell expends energy to transport materials into the cytosol. -The cell membrane pinches off to form an extracellular vesicle joined to the cell by filaments. -The cell membrane invaginates and pinches off, creating a vesicle within the cell. -The cell selectively filters small nutrients through specialized membrane pores. -The cell synthesizes proteins that pump large hydrophilic materials into the cell.

The cell expends energy to transport materials into the cytosol. The cell membrane invaginates and pinches off, creating a vesicle within the cell.

Which choice describes diffusion? -The movement of a substance across the cell membrane against its concentration with the help of transport proteins and ATP.ATP. -The movement of a substance across a cell membrane from an area of low concentration to an area of high concentration, up its concentration gradient. -The movement of a substance down its concentration gradient from a region where it is less concentrated to an area where it is more concentrated. -The movement of a substance from a region where it is more concentrated to a region where it is less concentrated, down its concentration gradient.

The movement of a substance from a region where it is more concentrated to a region where it is less concentrated, down its concentration gradient

What is an aquaporin? -a membrane protein that helps to anchor cells -a protein structure that allows direct communication between adjacent cells -a membrane protein that contains a channel for water movement -a glycoprotein that identifies the cell

a membrane protein that contains a channel for water movement

The movement of ions through this membrane protein is an example of passive transport. osmosis. endocytosis. active transport.

active transport.

Match each membrane protein to its correct function. Place all answers.

channel: contains a passage recognition: contains carbohydrate chain transport: uses energy to move substances receptor: recognizes and binds signal molecules enzymatic: metabolism chemical reactions junction: connect cells together

Place the appropriate plant cells in the isotonic, hypertonic, and hypotonic beakers.

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Facilitated diffusion is a protein‑facilitated movement of solutes across a membrane from an area of higher concentration to an area of lower concentration. Which of the terms best describes facilitated diffusion? active transport osmosis ion pump passive transport

passive transport

One way that cells engulf material from the environment is by ingesting solutes in the aqueous environment and enclosing them in intracellular vesicles. What is the name of this method of ingestion? transcytosis exocytosis pinocytosis phagocytosis

pinocytosis

Label the parts of a cell membrane with the term that describes each part.

see diagram

A and B are solutions of salt dissolved in water that are separated from each other by a semipermeable membrane in each scenario. Water can pass through this membrane, but the salt cannot. Match each pair of solutions to the net direction the water will flow between the two solutions.

solution A: 13% 4% solution B: 4% 14% solution C: 12% 12%

Select the statement that describes an electrochemical gradient. -sum of the differences in charge and chemical concentration of ions across a membrane -force acting on ions due to areas of opposite charge across a membrane -influence of membrane permeability on the net movement of ions across a membrane -any separation of ions across a membrane

sum of the differences in charge and chemical concentration of ions across a membrane