Biology Chapter 4 Inquizitive

Calcium ions (Ca^2+) are present at low concentrations in the blood but are needed at high concentrations by a variety of cells in your body. What type of transport is used to concentrate calcium in the cells that need it?

Active Transport.

T/F: Any type of transport that involves transport proteins is called active transport.

False.

Determine whether each of the following statements more accurately describes a hormone released by a body organ or a neurotransmitter released from a nerve cell.

Neurotransmitter: Acts in milliseconds, Very short lasting (milliseconds). Hormone: Long lasting, Acts in seconds to minutes, Acts in days months or years.

Amoeba are single-celled organisms that live in fresh water environments. Which of the following circumstances must amoeba be concerned about?

Removing water that enters the cell by osmosis.

Which of the following statements describe similarities between animal gap junctions and plant plasmodesmata?

Both gap junctions and plasmodesmata permit the cytoplasm of neighboring cells to connect. Both allow for direct communication between neighboring cells.

The concentration of carbon dioxide in a cell is 5%. The concentration of carbon dioxide in the blood running through the capillary next to the cell is 0.5%. What will happen?

Carbon dioxide will diffuse from the cell into the blood.

Sort the following properties of signaling molecules based on whether they would be more likely to bind to a cell surface receptor or an intracellular receptor.

Cell Surface Receptor: Large, Hydrophilic. Intracellular Receptor: Steroid sex hormone, Hydrophobic.

The protein insulin is released outside the cell and into the bloodstream through the process of ______. Insulin must be synthesized by ribosomes attached to the endoplasmic reticulum; it then travels to the ________, where it is packaged into a transport vesicle that moves to the ___________. Once there, the vesicle fuses to that structure, releasing its contents _________ the cell.

Exocytosis; Golgi apparatus; Plasma membrane; Outside of.

Sort the following molecules by their ability to cross the plasma membrane by simple diffusion or facilitated diffusion.

Facilitated Diffusion: Sugars, Amino Acids, Na^+. Simple Diffusion: Carbon dioxide, Water.

What is the main difference between simple diffusion and facilitated diffusion?

Facilitated diffusion requires a protein, whereas simple diffusion does not.

T/F: Endocytosis is used only to bring specific substances into the cell.

False.

What term is used to indicate a long- lasting signaling molecule that acts over long distances? In humans, many such signaling molecules are produced by the brain; the target cells of these signaling molecules are in other regions of the body.

Hormone.

A blood cell is placed in a solution, and within a few minutes, swells to twice its normal size and then bursts. The solution around the cell is _______ to the cytosol of the blood cell.

Hypotonic.

Why is cell-to-cell communication important in multi-cellular organisms?

Multi-cellular organisms are made up of many different cell types that need to communicate in order to coordinate their activities.

_______ is the transport of water across a selectively permeable membrane from regions with _____ solute concentration to regions of ______ solute concentration. This process __________ require energy.

Osmosis; Low; High; Does not.

Sort the protein types based on the type of transport in which each is involved.

Passive Transport: Channel protein, Carrier protein. Active Transport: Carrier protein.

Match the type of cell junction to its description.

Patches or belts of proteins between cells that are subject to heavy structural stress: Anchoring Junction. Belts of proteins that provide a leak-proof barrier between cells: Tight Junction. Tunnels formed by proteins that allow direct cytoplasmic connection between cells: Gap Junction.

What are the communication channels that extend through the cell walls of plants called?

Plasmodesmata.

In order to communicate, cells produce ______ molecules that travel throughout the body of a multi-cellular organism and attach to ______ proteins found on or in ______ cells. The interaction of these molecules result in a ________________ that may turn on genes that help the cell respond to the message it has received.

Signaling; Receptor; Target; Signal transduction pathway.

Which of the following statements is a result of the selective permeability of the plasma membrane?

The chemical composition of the cytoplasm is different from the chemical composition of the environment. Small and uncharged molecules can pass directly through the plasma membrane, but large and charged molecules cannot.

Plant cells do not have structures similar to anchoring junctions and tight junctions. Why?

The plant cell wall performs some of the functions of anchoring and tight junctions, which are specialized regions of the animal cell membrane. The cell wall also prevents contact between the cell membranes of adjoining plant cells.

Solution A (25% sucrose) is separated from solution B (10% sucrose) by a selectively permeable membrane. Sucrose cannot cross the membrane. Which of the following statements are valid?

The volume of solution A may increase. Water will move from solution B to solution A.

Define Exocytosis:

Transportation of large molecules out of the cell via the formation of a vesicle.

T/F: Active transport is used to move substances against their concentration gradient.

True.

T/F: The fastest working signaling molecules are those that are released by nerve cells.

True.

T/F: The intracellular receptors that bind to hydrophobic signaling molecules can activate specific genes in the nucleus of the cell receiving signal.

True.