biol 1406 final

The four major classes of biological macromolecules are

Carbohydrates, Lipids, Proteins, Nucleic Acids

Which four elements make up about 96% of human body weight?

C, H, O, N

Why are most cells small?

To maximize diffusion efficiency

What is the primary structural component of the cell membrane?

phospholipids

Cohesion refers to water molecules

Sticking to each other

What is passive transport?

movement down concentration gradient

Which microscope uses a beam of electrons to scan the surface of a specimen?

Scanning electron microscope

What is the function of magnetososmes in bacteria?

magnetic alignment

Deductive reasoning involves

General principles' specific predictions

What role does cholesterol play in membrane fluidity?

stabilizes fluidity across temperatures

Which type of membrane proteins spans the entire membrane?

integral proteins

Which level of biological organization represents a group of populations living together in one place?

Community

A substance that increases H+ concentration in a solution is called

Acid

Which process builds polymers from monomers?

Dehydration synthesis

Waters high specific heat is mainly due to

Hydrogen bonds

Which particle carries a negative charge?

Electron

Which type of lipid is found in membranes and has a sphingosine backbone?

sphingolipids

A hypothesis must

Be tested and falsifiable

The monomer of carbohydrates is a

Monosaccharide

What is the main structural component of bacterial cell walls?

peptidoglycan

What effect do unsaturated fatty acids have on membrane fluidity?

increase fluidity

Who first observed cells under a microscope in 1665?

Hooke

Which type of bond involves the sharing of electrons?

Covalent

Emergent properties are best described as

Traits of a system that arise from interactions of parts

Darwins theory of natural selection states that

Favorable traits increase survival and reproduction

The monomers of proteins are

Amino acids

Atoms of the same element with different numbers of neutrons are called

Isotopes

Which of the following is not part of the Cell Theory?

Cells arise from non-living matter

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

Color of the cell

The basic unit of life is the

Cell

Glucose and fructose are examples of

Monosaccharides

Which variable is manipulated in an experiment?

Independent variable

What is the function of transmembrane proteins?

transport across membranes

What model describes the structure of cell membranes?

fluid mosaic model

Buffers resist changes in pH by

Removing or adding H+ ions

As a cell increases in size, what happens to its surface area-to-volume ratio?

It decreases

Which bond is the strongest?

Triple covalent

Which of the following is a characteristic of prokaryotic cells?

circular DNA

Which of the following is a core concept of biology?

Structure determines function

The carboxyl group (COOH) acts as

An acid

What powers bacterial flagella

Proton gradient

Cellulose differs from starch in that

It is composed of Beta-glucose linkages

Which evidence supports evolution?

Fossil record, Comparative anatomy, Molecular similarities
All of the above

Which functional group is characteristic of alcohols?

OH

Which of the following is not a characteristic of all living organisms?

Lack of energy use

Which of the following is NOT a component of cellular membranes?

DNA

Hydrolysis reactions

Break polymers into monomers using water

Which disaccharide is composed of glucose + fructose?

Sucrose

Which part of a phospholipid is hydrophobic?

fatty acid tails

When sodium donates an electron to chlorine to form NaCl, sodium is

Oxidized

When investigating the enzyme Rubisco, the group finds it is less efficient at high O₂ levels. What process does this inefficiency lead to?

Photorespiration

A steroid hormone enters a cell and binds to a receptor in the cytoplasm. What happens next?

Receptor-hormone complex moves to the nucleus to regulate gene expression

The team observes that corn plants maintain higher photosynthetic rates under hot, dry conditions compared to spinach. Which adaptation explains this?

Use of PEP carboxylase for initial CO₂ fixation

A mutation prevents NADH from being oxidized back to NAD⁺ in a muscle cell. What would happen next?

Glycolysis would halt due to a lack of NAD⁺

A lab experiment shows reduced reaction rate despite high substrate concentration. What does this suggest?

Enzyme saturation

In cactus plants, the group detects that CO₂ fixation occurs at night and sugar synthesis occurs during the day. This describes:

CAM photosynthesis

An athlete relies on carbohydrates for energy during a race. What role does ATP play in this process?

Provides energy for muscle contraction

A student is studying channel-linked receptors. What is their primary function?

Allow specific ions to pass through the membrane when activated

The students notice that liver cells divide more slowly than skin cells. This is most likely because:

Liver cells often remain in G0 phase for extended periods

During glycolysis, the researcher measures a net production of 2 ATP and 2 NADH per glucose molecule. What type of ATP production occurred?

Substrate-level phosphorylation

A researcher blocks APC/C activity during cell division. Which stage would most likely be affected?

Anaphase

A signal molecule binds to a GPCR and activates a G protein. What happens next?

The G protein activates an effector, leading to second messenger production  

An enzyme loses activity at normal body temperature. What is the most probable cause?

Altered enzyme shape due to pH or temperature changes

The research group notes that both photosynthesis and respiration involve electron transport chains. What is a key difference between them?

Photosynthesis builds up energy, while respiration releases it

A hormone travels through the bloodstream and affects distant cells. What type of signaling is this?

Endocrine

A neuron releases neurotransmitters that act on a nearby muscle cell. What kind of signaling is this?

Synaptic

During mitosis, spindle fibers attach to chromosomes at a specialized region called the:

Centromere

Which of the following correctly compares aerobic respiration and fermentation?

Aerobic respiration uses the electron transport chain; fermentation does not.

A patient with a metabolic disorder shows reduced ATP levels. What is the most likely consequence of this condition?

Impaired muscle contraction and nerve signaling

Under laboratory light, Photosystem II (PSII) in corn chloroplasts is found to split water. What is the primary purpose of this reaction?

To replace electrons lost by chlorophyll a

In human cell cultures, researchers notice that certain cells stop dividing after damage to their DNA. This demonstrates the function of:

p53 checkpoint control

A mutation prevents a G protein from exchanging GDP for GTP. What is the likely consequence?

The signal transduction pathway is blocked

The researcher notices that in an anaerobic chamber, muscle cells continue to produce small amounts of ATP. Which process allows this to happen?

Lactic acid fermentation

A defect in mitochondrial membranes that prevents proton buildup would directly interfere with which process?

Chemiosmosis

A mutation prevents an enzyme from binding its substrate. What structural feature is most likely affected?

Active site shape

A researcher observes that a cell responds only to specific signals despite being exposed to many. What determines this selective response?

Number and type of receptors on the cell surface

A cell biologist discovers a tumor where cells continuously divide without external signals. Which mutation best explains this?

activation of oncogenes that constantly trigger division 

When comparing pigments, the group notes that chlorophyll a absorbs blue and red light, while carotenoids absorb blue and green light. What is the role of carotenoids?

Capture additional wavelengths and protect from oxidative damage

A scientist studies a skin cell preparing to divide. During the S phase of the cell cycle, what is happening?

DNA is replicated, forming sister chromatids

In a bacterial species capable of anaerobic respiration, which molecule could serve as the final electron acceptor instead of oxygen?

sulfur

During one experiment, the CO₂ concentration is increased around the spinach leaves, which enhances sugar production. This supports that:

CO₂ is used in the Calvin cycle for carbon fixation

Photosynthesis begins in a plant cell exposed to light. What happens to the energy?

Captured and stored in chemical bonds

During one bacterial experiment, a mutation disables the FtsZ protein. What would most likely happen?

Septum would not form properly, preventing cell division

A new cancer therapy targets CDK1 to prevent activation of mitosis-promoting factor (MPF). What would this drug inhibit?

Transition from G2 to M phase

A toxin disrupts redox reactions in cells. What is the likely effect?

Impaired cellular respiration and energy flow

In a cell where ATP levels are high, the enzyme phosphofructokinase becomes inhibited. What is the likely outcome?

Glycolysis slows down due to feedback inhibition

A student blocks ATP synthase channels in chloroplasts. What is the most immediate consequence?

Chemiosmosis will stop and ATP synthesis will decline

In an experiment, a chromosome remains condensed and fails to uncoil after mitosis. Which phase was likely disrupted?

Telophase

A student research group is investigating how different environmental conditions affect the rate of photosynthesis in several plant species, including spinach (C₃), corn (C₄), and cactus (CAM). They use a light meter, CO₂ analyzer, and chlorophyll fluorescence sensor to track photosynthetic activity under various conditions. The group measures that spinach plants rapidly increase O₂ production under bright light but slow down in low light. What does this indicate about photosynthesis?

Light intensity affects the rate of light-dependent reactions

A cell uses direct contact signaling during early development. What does this involve?

Membrane-bound molecules interacting with neighboring cells 

If pyruvate oxidation is inhibited in mitochondria, what is the most likely immediate result?

Enhanced function of the electron transport chain

A team of biology students studies cell division in both bacteria and human tissue cultures. They explore how genetic regulation, checkpoints, and mitotic mechanisms ensure healthy growth and what happens when those processes fail.

The team observes that bacterial cells divide much faster than eukaryotic cells. What explains this difference?

Bacteria have a single circular chromosome and a simpler division process

A metabolic pathway shuts down when product concentration increases. What mechanism is responsible?

Feedback inhibition via allosteric binding

An experiment comparing ATP yields shows that eukaryotic cells produce about 30 ATP per glucose, while prokaryotes can produce up to 32 ATP. What explains this difference?

Eukaryotes lose ATP transporting molecules into mitochondria

Students observe that when plants are switched to a red-only light source, ATP synthesis continues, but less NADPH is formed. Which process is being emphasized?

Cyclic photophosphorylation

A student compares exergonic and endergonic reactions. Which statement is correct?

Exergonic reactions are spontaneous and release energy

A cell is exposed to a signal that activates a receptor kinase. What cellular processes might be affected?

Cell cycle, migration, metabolism, and proliferation

A patient is given a drug that mimics a natural ligand and binds to a receptor on the cell surface. What is the most likely result?

A signal transduction pathway is initiated

A cell shows no increase in reaction rate despite more substrate. What does this indicate?

All active sites are occupied

A researcher is studying how cells extract energy from glucose under various conditions. She analyzes yeast, muscle, and bacterial cells to observe how oxygen availability and enzyme activity affect ATP production.

When oxygen is present, pyruvate produced from glycolysis in yeast is most likely converted into:

Acetyl-CoA