Semester 1 bio exam (1/2) Flashcards
What is the primary characteristic of science that allows it to constantly evolve?
Constant testing and revision
Which of the following is NOT a goal of science?
Proving supernatural events
How do scientists primarily approach new information?
By evaluating it based on evidence
What is the term for the process of observing and asking questions about the natural world in an organized way?
Scientific method
Which statement best describes the nature of scientific facts?
They are subject to revision based on new evidence
What is the primary focus of scientific research?
Natural phenomena
How do scientists typically propose explanations for observed phenomena?
Based on evidence and understanding
What does it mean when scientific discoveries raise more questions than answers?
Science is progressing and new avenues for study are opening
Which of the following is NOT a part of scientific methodology?
Accepting conclusions without questioning
What is an inference in scientific terms?
A logical interpretation based on existing knowledge
In a controlled experiment, what is the independent variable?
The variable that is changed by the experimenter
What is the primary purpose of a control group in an experiment?
To provide a basis for comparison
Which type of data involves characteristics that usually can’t be measured numerically?
Qualitative data
What is a scientific theory?
A highly-tested, reliable explanation of natural events
Which of the following is NOT considered a scientific attitude?
Closed-mindedness
What is the primary purpose of peer review in scientific research?
To allow evaluation and testing of data and analysis
What is bias in scientific terms?
A personal, non-scientific point of view
Which of the following is NOT a field of biology mentioned in the text?
Astrophysics
What is homeostasis in living organisms?
Maintaining a relatively constant set of internal conditions
What is the primary characteristic of science that distinguishes it from other ways of explaining the world?
It uses evidence to construct testable explanations
Which of the following best describes the nature of scientific knowledge?
It is constantly changing and evolving
What is the main goal of science?
To understand the interactions of parts and processes in the physical universe
What is the basic unit of matter?
Atom
Which subatomic particle is found outside the nucleus and has a negative charge?
Electron
What is the atomic number of an element determined by?
Number of protons
Which of the following is NOT one of the six elements that make up about 99% of living things?
Potassium
What is the term for atoms of the same element with different numbers of neutrons?
Isotopes
What is the total number of protons and neutrons in an atom’s nucleus called?
Atomic mass
Which isotope of carbon has 6 protons and 8 neutrons?
Carbon-14
What is a chemical combination of two or more elements in definite proportions called?
Compound
In the compound NaCl, what type of chemical bond is formed between sodium and chlorine?
Ionic bond
What happens when an atom loses electrons?
It becomes positively charged
In a covalent bond, what is shared between atoms?
Electrons
What is the smallest unit of most compounds?
Molecule
Which force produces slight attraction between molecules when they are very close?
Van der Waals force
What is the chemical formula for water?
H2O
In a water molecule, which atom has a stronger attraction for electrons?
Oxygen
What type of bond is formed between water molecules?
Hydrogen bond
Which of the following is a characteristic of radioactive isotopes?
They break down at an unpredictable rate
What is the charge of a neutron?
Neutral
How does the mass of an electron compare to that of a proton?
It is 1/1840 the mass
Which of the following best describes a polar covalent bond?
Unequal sharing of electrons, resulting in partial charges
Which two types of particles are present in equal numbers in an atom, but not in an ion?
Protons and electrons
The elements sodium and chlorine react to form the chemical compound sodium chloride. How would you predict the properties of sodium chloride compare with those of its constituent elements?
Very different
What is the primary reason water can form multiple hydrogen bonds?
Its polarity
What is cohesion in the context of water molecules?
Attraction between molecules of the same substance
Why does water have a high heat capacity?
Because it can form multiple hydrogen bonds
What is an example of a solution?
Salt dissolved in water
What property of water allows it to dissolve ionic compounds and polar molecules?
Polarity
What happens when water has dissolved all the solute it can?
It becomes saturated
What is a suspension?
A mixture of water and undissolved material
What is the pH of a neutral solution?
7
Which of the following substances is considered an acid?
Vinegar
What is the pH value of bleach?
12.5
What is the function of buffers in biological systems?
To prevent sharp changes in pH
What ions do acids release into a solution?
Hydrogen ions
How many times more hydrogen ions does a solution with a pH of 4 have compared to a solution with a pH of 5?
10 times
What is the primary solvent in blood?
Water
Which property of water contributes to surface tension?
Cohesion
What is the term for the attraction between molecules of different substances?
Adhesion
What is an example of an ionic compound that water can dissolve?
Salt
What does it mean if a solution is basic?
It has more hydroxide ions than hydrogen ions
Why is water essential in living organisms?
It is a medium for chemical reactions
What happens when water molecules split?
They form hydrogen ions and oxygen ions
Who first used the term ‘cells’ to describe the chambers observed in cork?
Robert Hooke
The cell theory states that all living things are composed of what?
Cells
What is a limitation of light microscopes?
Images are clear up to a magnification of about 1000 times
What type of microscope uses beams of electrons?
Electron microscope
Why are chemical dyes or stains used in light microscopy?
To make cells and their parts visible
Which type of electron microscope is used to explore cell structures and large protein molecules?
Transmission electron microscope
What is a characteristic of a scanning electron microscope (SEM)?
Produces 3-dimensional images
What conclusion did Matthias Schleiden make in 1838?
All plants are made of cells
Which scientist used a microscope to observe pond water and discovered tiny living organisms?
Anton van Leeuwenhoek
How small can electron microscopes see?
1 billionth of a meter
What is a major disadvantage of using electron microscopes?
They can only examine nonliving cells and tissues
Which of the following is not part of the cell theory?
Cells can spontaneously generate
What is the main difference between prokaryotic and eukaryotic cells?
Presence of a nucleus
Which of the following structures encloses the genetic material in a eukaryotic cell?
Nucleus
What type of organism are cyanobacteria classified as?
Prokaryotes
Which characteristic is common to all prokaryotic cells?
They lack membrane-bound organelles
How did the first photosynthetic organisms impact Earth’s atmosphere?
They reduced carbon dioxide levels
What type of organism are cyanobacteria classified as?
d. Prokaryotes
Which characteristic is common to all prokaryotic cells?
c. They lack membrane-bound organelles
How did the first photosynthetic organisms impact Earth’s atmosphere?
d. They increased oxygen levels
Which type of cell is generally larger and more complex?
a. Eukaryotic
Which of the following is an example of a eukaryotic organism?
a. Fungi
What role do bacteria play in the environment?
c. They play important roles such as decomposition and nitrogen fixation
Which of the following is NOT a characteristic of eukaryotic cells?
a. They are always unicellular
Which group does NOT include eukaryotic organisms?
d. Bacteria
What is the main function of the nucleus in a cell?
c. To act as the control center of the cell
What is passive transport?
b. Movement of molecules without using cellular energy
What is homeostasis?
c. A state of relatively constant internal physical and chemical conditions
How does diffusion occur?
a. By moving particles from a higher to a lower concentration
What is equilibrium in the context of diffusion?
a. When the concentration of particles is the same on both sides
What is facilitated diffusion?
d. Diffusion through special protein channels without energy
What role do aquaporins play in cells?
c. They allow water to pass through the cell membrane
How does osmosis differ from simple diffusion?
c. Osmosis involves the diffusion of water through a membrane
What does isotonic mean?
a. The solute concentration is the same on both sides of the membrane
Which solution is considered hypertonic?
a. The side with higher solute concentration
What is hypotonic solution?
d. A solution with a lower solute concentration
What is osmotic pressure?
b. The difference in solute concentration that causes water movement
Why do cells in large organisms not burst when in contact with fresh water?
b. They actively pump out excess water
What happens when a cell is in a hypertonic solution?
a. The cell will shrink
What is the primary function of protein channels in facilitated diffusion?
b. To allow large or polar molecules to pass through the cell membrane
What is a key characteristic of passive transport?
a. It does not require energy
Which of the following best describes osmosis?
b. Movement of water from high to low concentration through a membrane
What condition occurs when the concentration of solutes is the same inside and outside the cell?
d. Isotonic
How do cells maintain homeostasis?
b. By regulating the movement of molecules across the membrane
Which statement about facilitated diffusion is true?
c. It involves the use of protein channels
What occurs when a cell is placed in a hypotonic solution?
b. It gains water and swells
What is active transport?
c. Movement of materials against a concentration difference requiring energy
Which type of transport involves proteins acting like pumps?
a. Passive transport
What is the role of protein pumps in cells?
b. To move ions like calcium, potassium, and sodium across the cell membrane
Which component is NOT directly involved in the light-dependent reactions of photosynthesis?
b. Carbon dioxide
What is the primary function of ATP synthase in photosynthesis?
c. To allow H+ ions to pass through and produce ATP
In the electron transport chain, what is the original source of replacement electrons?
a. Water molecules
