Q: Which of the following is a correct formula for calculating the mean of a data set?

$\text{Mean} = \frac{\sum x_i}{n}$

Question 1

Which property of water is primarily responsible for its ability to dissolve many biological molecules, making it an effective solvent in living systems?

Accepted Answer

Its polarity and ability to form hydrogen bonds

Question 2

A scientist wants to test whether a new enzyme increases the rate of starch breakdown. Which of the following best describes a valid experimental design?

Accepted Answer

Compare starch breakdown in two identical samples, one with enzyme and one without, while controlling temperature and pH.

Question 3

Which of the following best explains why ice floats on water?

Accepted Answer

Ice is less dense than liquid water due to hydrogen bonding creating an open lattice structure.

Question 4

Which macromolecule is primarily responsible for storing genetic information in cells?

Accepted Answer

DNA

Question 5

A student collects data on enzyme activity at different pH levels. Which statistical test should they use to determine if the differences in activity are significant?

Accepted Answer

t-test

Question 6

Which of the following best describes the process of dehydration synthesis?

Accepted Answer

Joining two monomers by removing a water molecule

Question 7

Given the following data for enzyme activity at different temperatures: 10°C (5 units), 20°C (15 units), 30°C (25 units), 40°C (10 units). What is the most likely explanation for the decrease in activity at 40°C?

Accepted Answer

The enzyme denatures at higher temperatures, losing its functional shape.

Question 8

Which of the following is a correct representation of the chemical formula for glucose?

Accepted Answer

$C_6H_{12}O_6$

Question 9

A researcher wants to test the hypothesis that increasing salt concentration decreases enzyme activity. Which is the null hypothesis?

Accepted Answer

Salt concentration has no effect on enzyme activity.

Question 10

Which of the following best describes the role of phospholipids in biological membranes?

Accepted Answer

They form a bilayer that creates a selective barrier between the cell and its environment.

Question 11

Which of the following is a correct formula for calculating the mean of a data set?

Accepted Answer

$	ext{Mean} = \frac{\sum x_i}{n}$

Question 12

Which of the following statements about proteins is correct?

Accepted Answer

Proteins are polymers made of amino acids linked by peptide bonds.

Question 13

A student is analyzing a graph showing enzyme activity over time. What is the best way to represent the rate of reaction from the data?

Accepted Answer

Calculate the slope of the line during the linear phase of the reaction.

Question 14

Which of the following is a correct formula for calculating the percentage of a part relative to the whole?

Accepted Answer

$	ext{Percentage} = \frac{	ext{Part}}{	ext{Whole}} 	imes 100$

Question 15

Which of the following best explains the difference between DNA and RNA?

Accepted Answer

DNA contains deoxyribose sugar and is double-stranded; RNA contains ribose sugar and is single-stranded.

Question 16

A scientist observes that water beads up on a waxy leaf surface. Which property of water is most responsible for this phenomenon?

Accepted Answer

Cohesion

Question 17

Which of the following is a correct formula for calculating the ratio of two quantities?

Accepted Answer

$	ext{Ratio} = \frac{A}{B}$

Question 18

Which of the following best describes the function of carbohydrates in living organisms?

Accepted Answer

They provide energy and serve as structural components.

Question 19

A student is asked to analyze a set of data showing the effect of pH on enzyme activity. Which of the following is the best way to visually represent this data?

Accepted Answer

Plot a line graph with pH on the x-axis and enzyme activity on the y-axis.

Question 20

Which of the following is a correct formula for calculating the standard deviation of a data set?

Accepted Answer

$	ext{SD} = \sqrt{\frac{\sum (x_i - \bar{x})^2}{n-1}}$

General Biology Study Notes: Science Practices and Biological Molecules

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