The molecule to the right represents the structure of a monomer for a macromolecule.  The part in the box represents glycerol.  What is the rest of the monomer made of?

• Monosaccharide

• Fatty acid tails

• amino acid

• nucleotides

Answer explanation

The monomer structure includes glycerol and is typically associated with lipids. The remaining part, which is not glycerol, consists of fatty acid tails, making it a triglyceride or similar lipid structure.

Tags

NGSS.MS-LS1-7

NGSS.MS-PS1-1

Which of the following could represent a possible gamete from an organism whose somatic cells have the genotype AArrEe as a result of meiosis?

• ArE

• AArrEe

• AArEe

• Arre

Answer explanation

The organism's genotype AArrEe can produce gametes with one allele from each gene. The correct gamete ArE includes one A, one r, and one E, while the other options either have too many alleles or do not follow the haploid condition.

Tags

NGSS.HS-LS3-2

Two samples of macromolecules are tested. Sample A contains nitrogen and is made of amino acids. Sample B contains only carbon, hydrogen, and oxygen and provides quick energy. What are the likely macromolecules each sample represents?

• Sample A: Carbohydrate; Sample B: Protein

• Sample A: Nucleic acid; Sample B: Lipid

• Sample A: Protein; Sample B: Carbohydrate

• Sample A: Lipid; Sample B: Nucleic acid

Answer explanation

Sample A contains nitrogen and is made of amino acids, indicating it is a protein. Sample B, containing only carbon, hydrogen, and oxygen, provides quick energy, which is characteristic of carbohydrates.

Tags

NGSS.MS-LS1-7

Which of the following best explains why lipids are ideal for forming the cell membrane?

• Their hydrophobic tails prevent free movement of water-soluble substances.

• Their monomers dissolve easily in water and pass through the membrane.

• They contain nitrogen and can bond with proteins in the cytoplasm.

• They fold into specific shapes that allow enzymes to catalyze reactions.

Answer explanation

Lipids have hydrophobic tails that create a barrier, preventing water-soluble substances from freely passing through the cell membrane. This property is essential for maintaining the integrity and functionality of the cell.

A biologist isolates an unknown macromolecule that folds into a specific 3D shape and becomes nonfunctional when exposed to high heat. Based on this, which macromolecule is it most likely to be, and why?

• Lipid, because lipids form membranes and are heat-sensitive

• Protein, because its function depends on shape and denatures at high temperatures

• Carbohydrate, because sugars are used for short-term energy

• Nucleic acid, because it stores genetic information and is easily broken by heat

Answer explanation

The macromolecule is most likely a protein, as its function is highly dependent on its 3D shape. High heat causes proteins to denature, losing their functional shape, which aligns with the observation of nonfunctionality upon heating.

Tags

NGSS.MS-LS3-1

The images shows interactions between water molecules. Which image best represents the interaction between two water molecules?

• A

• B

• C

• D

Answer explanation

Image B best represents the interaction between two water molecules, showing hydrogen bonds. These bonds occur due to the polar nature of water, where the positive hydrogen of one molecule attracts the negative oxygen of another.

Tags

NGSS.MS-PS1-4

NGSS.MS-PS3-4

The diagram compares the vacuole in an animal and a plant cell. Which of the  following statements correctly compares the vacuole in both types of cells?

• Animal cells have a large central vacuole for water storage, while plant cells do not.

• Plant cells have a large central vacuole that helps maintain turgor pressure, while animal cells have smaller vacuoles.

• Both plant and animal cells use the vacuole mainly for protein synthesis.

• Animal cells use vacuoles to maintain turgor pressure for structural support.

Answer explanation

Plant cells have a large central vacuole that maintains turgor pressure, essential for structural support. In contrast, animal cells have smaller vacuoles that do not serve this function, making the second statement correct.

Tags

NGSS.MS-LS1-2

Which scenario best explains how molecules move from a lower to a higher concentration across a membrane using energy and a transport protein?

• Molecules pass directly through the phospholipid bilayer along their concentration gradient without energy input by diffusion.

• Molecules use a channel protein to move passively from high to low concentration without requiring ATP by facilitated diffusion.

• Molecules are pumped through a membrane protein using ATP to move against their concentration gradient by active transport.

• Water molecules move through aquaporins from an area of low solute concentration to high solute concentration by osmosis.

Answer explanation

The correct choice describes active transport, where molecules are pumped through a membrane protein using ATP to move against their concentration gradient, which requires energy.

A student wanted to know how the concentration of sugar in a solution 

surrounding a cell affects the movement of water. An experiment was set up using potato cylinders to represent cells.

Based on the information provided for the experiment, correctly match each of the following to its role in the experiment.​

• movement of water

• Independent Variable

• size of potato pieces

• Dependent Variable

• sugar concentration

• Constant

Answer explanation

In the first sentence that explains what the scientist is doing.... the IV is always written first then comes the DV

The effect of IV on DV

Tags

NGSS.MS-LS2-1

NGSS.MS-LS2-4

A student wanted to know how the concentration of sugar in a solution surrounding a cell affects the 

movement of water. An experiment was set up using potato cylinders to represent cells.

Based on this experiment, in which solution would a cell likely increase the most in mass?

• In a 1 mol/dm³ sugar solution, water will move into the cell because the solution is highly concentrated compared to the cell.

• In a 0.8 mol/dm³ sugar solution, less water will move into the cell because the solution is less concentrated compared to the cell.

• In a 0.2 mol/dm³ sugar solution, water will move into the cell because the solution is more diluted compared to the other concentrations.

• In pure water, water concentration is higher than inside the cell, causing water to move into the cell.

Answer explanation

In pure water, the concentration of water is higher outside the cell than inside. This causes water to move into the cell by osmosis, leading to an increase in mass.