BIOL 1334 week two

Facilitated diffusion Correct

1. What is the means of transport for large molecules and ions?

true

A 5% urea solution is hypotonic to a 10% urea solution.

cell, 3, cell membrane, nucleus, cytoplasm, organelles, cytoplasm

A cell is the basic unit of an organism and is composed of 3 major parts. The cell membrane forms the outer most layer of the cell. The nucleus contains DNA and directs the cell's functions. The cytoplasm contains small organs known as organelles and a liquid called the cytosol.

true

A molecule or ion that crosses the membrane by moving down a concentration gradient and without expenditure of cellular energy is said to be transported passively. 1. Another name for the process described is diffusion.

shrink

A red blood cell placed in a hypertonic medium will:

first

A single base change in the DNA base order might impact the final protein product of the transcription/translation process IF the base change alters the amino acid called for during translation. It is an alteration in the _____ base of a codon that is most likely to result in a change in the amino acid placed the final protein product.

releasing the terminal phosphate group and the energy associated with the bond.

ATP molecules provide energy for cellular activities by:

portions

Almost all enzymes are:

F

An enzyme speeds up a chemical reaction in the cell, but can only be used once.

true

Apoptosis is a normal part of development.

atoms, molecules, macromolocules.

At the chemical level, atoms combine to form molecules, which combine to form macromolecules. The cell is the basic unit of structure and function, and contains small structures called organelles, that are, in turn, composed of macromolecules. There are 11 different organ systems in the human body, formed when these cells organize into tissues and organs. Each organ system has a different set of functions, though all systems are interdependent. Human cells have a nucleus, a cell membrane, and cytoplasm. However, not all cells are the same. The different functions of a cell, and thus of an organ and organ system, will require a difference in quantity and type of organelles within those cells.

anabolic, Catabolic

Chemical reactions in which large molecules are built from small molecules are classified as ______ reactions. In contrast, ______ reactions involve breaking large molecules down into smaller ones.

t

DNA replication results in two identical daughter molecules each consisting of one old (original) strand and one newly-synthesized strand.

In either direction depending on the concentration gradient of the molecule.

Describe where facilitated diffusion occurs.

true

Diffusion is one of the processes whereby materials are exchanged between a cell and its environment.

false

Each mRNA molecule is used to produce one copy of a protein molecule.

oxidation

Energy needed for cellular function comes from the "burning" or _____ of glucose, fats, and protein.

true

Facilitated diffusion is similar to simple diffusion, but will also allow movement due to electrical gradients.

sugars / amino acids

Facilitated diffusion is used to transport:

carrier protiens

Facilitated diffusion requires:

true

If a cell is placed in an isotonic medium, there will be no net movement of water.

T-A-A-C-G-T

If one strand of DNA had a base sequence of A-T-T-G-C-A, what base order would be found on the complementary strand of DNA?

t

If there was 100mEq of Na+ inside the cell and 50mEq of Na+ outside the cell, the concentration is said to be higher inside the cell.

true

If there were many Na+ ions outside a cell and only a few inside the cell, active transport could be used to pump Na+ out of the cell.

thymine, uracil

In these activities, you practiced matching complementary bases, just as occurs during DNA replication, transcription, and translation. During replication, adenine complements ______. During transcription and translation, adenine complements ______.

true

Ions also have a hard time crossing the cell membrane because they typically have many water molecules bound to them and therefore are larger.

1. Cytosine Guanine Correct 2. Adenine (DNA) Thymine Correct 3. Adenine (RNA) Uracil

Match the DNA and RNA nucleotides with their complimentary base.

answers ->

Normal saline solution is isotonic to the human blood cells. A cell placed in a hypotonic solution will expand. A hypertonic solution has a solute concentration higher than the solute concentration inside the cell. Cells that are experiencing a net movement of water towards the ECF due to osmosis are bathed in hypertonic solutions. Distilled water given intravenously will cause cells to expand due to rapid movement of water into the cells via osmosis.

water molecules across a membrane from an area of high water concentration to an area of lower concentration.

Osmosis is best defined as the movement of:

answers ->

Ribosomes: site of protein synthesis Mitochondria: site of reactions that release energy from food substances Golgi apparatus: modifies and packages proteins for transport and secretion Lysosomes: contain enzymes necessary for digesting substances that enter the cell Peroxisomes: contain enzymes that catalyze metabolic reactions that release hydrogen peroxide

nucleus, cytoplasm, and cell membrane

Specialized structures found in the cytoplasm of the cell are called ___.

organelles

Specialized structures found in the cytoplasm of the cell are called ___.

false

The key to remember about osmosis is that water flows from the solution with the higher solute concentration into the solution with lower solute concentration.

false

The molecules in a solid lump of sugar do not move.

The order of nitrogenous bases in DNA determines the order of nitrogenous bases in mRNA, which determines the order of amino acids in protein.

The order of nitrogenous bases in DNA determines the order of nitrogenous bases in mRNA, which determines the order of amino acids in protein.

answers

The specific order of amino acids in a protein is determined by the order of nitrogenous bases in a segment of DNA called a gene. Each amino acid is "coded for" by several possible sequences of 3 bases. The base sequence of DNA determines the base sequence in the molecule called mRNA, which carries the genetic information from the nucleus to the cytoplasm. In an mRNA molecule, each 3-base sequence is called a codon. Any one amino acid can be coded for by several of these 3-base sequences. For example, the base sequences CUU, CUC, CUA, and CUG within the mRNA will all result in the amino acid leucine being placed within the protein molecule being built.

answers ->

The term metabolism refers to all of the chemical reactions in cells that acquire, store, and release energy. Metabolic reactions that assemble smaller molecules into larger molecules are called anabolic reactions and those that break down larger molecules into their smaller components are called catabolic reactions. Catabolic reactions release energy, while anabolic reactions require energy. These metabolic reactions are controlled by catalysts called enzymes.

codons, anticodons

The three-base sequences on mRNA that code for a particular amino acid are called codons . The complementary three-base sequences on tRNA are called anticodons .

answers

Three-base sequences on mRNA, called codons, code for individual amino acids. With four possible bases forming each 3-base sequence, it is possible to form 64 combinations. Of all the possible 3-base sequences, three act as stop sequences, marking the end of the genetic information for that gene. This leaves 61 possible 3-base combinations to code for 20 amino acids. Due to having multiple possible codons for any one amino acid, a change in one base within a codon may or may not code for a different amino acid in the final protein.

t

Together, gradients in concentration and electric potential across the cell membrane constitute the electrochemical gradient that governs passive transport mechanisms.

E + S → ES → EP → E + P

Using "E" for enzyme, "S" for substrate, and "P" for product, indicate the best representation of the mechanism of enzyme function.

95% concentration outside: 45% concentration inside Correct

Water, oxygen, carbon dioxide, ethanol, and urea are examples of molecules that readily cross cell membrane by simple diffusion. They pass either directly through the lipid bilayer or through pores created by certain integral membrane proteins. The relative rate of diffusion is roughly proportional to the concentration gradient across the membrane. For example, oxygen concentrations are always higher outside than inside the cell. Therefore, oxygen diffuses down its concentration gradient into the cell. 1. Which concentration gradient would result in a faster diffusion of oxygen?

substrate

What binds to the active site of an enzyme?

DNA sequence used to make a particular protein

What is the definition of the term gene?

osmosis

What is the special name for the diffusion of water across a membrane?

mRNA is produced from a DNA template.

What occurs during the phase of protein synthesis called transcription?

A polypeptide is built, based on mRNA base sequence.

What occurs during the stage of protein synthesis called translation?

the dissolved sugar molecules are evenly distributed throughout the solution.

When sugar is mixed with water, equilibrium is reached when:

amount of atp

Which of the following does not affect the rate of diffusion?

ions

Which of the following might NOT follow passive diffusion simply because of a concentration gradient?

exocytosys

Which of the following represents the bulk movement of material out of the cell using energy?

small non polar

Which of the following will pass through a cell membrane most easily?