Biology III : Final Exam

Which element is not one of the four most common elements in living organisms?

Calcium

What type of bond forms when electrons are shared between atoms?

Covalent bond

Which property of water allows it to stick to plant xylem and travel upward?

Cohesion and adhesion

What type of macromolecule is used for long-term energy storage?

Lipids, including fats and oils

Which monomer pairs correctly with its macromolecule?

Amino acids - Protein

Which property allows ice to float on water?

Lower density as a solid

What does a PH of 3 indicate?

Strong acid

What is the main difference between prokaryotic and eukaryotic cells?

Eukaryotes have a nucleus

Which organelle packages and ships proteins?

Golgi apparatus

Which organelles is responsible for energy (ATP) production?

Mitochondria

The cell membrane is described as:

Selectively permeable

Ribosomes function to:

Synthesize proteins

Enzymes speed up chemical reactions by:

Lowering activation energy

What happens to enzyme activity when the pH is too high or low?

Enzyme denatures

In competitive inhibition:

The inhibitor binds the active site

The lock and key model describes:

Specificity of enzymes for substrates

Which molecule is the main energy currency of the cell?

ATP

What is the correct order of the steps in aerobic respiration?

Glycolysis → Krebs cycle → Electron transport chain

Which stage of aerobic respiration produces the most ATP?

Electron Transport Chain

During glycolysis, glucose is broken down into:

Pyruvate

In the absence of oxygen, what process occurs in muscle cells?

Lactic acid fermentation

What are the products of the light-dependent reactions?

ATP and NADPH

Which pigment is essential for photosynthesis?

Chlorophyll a

Where does the Calvin Cycle occur?

Chloroplast stroma

The overall function of photosynthesis is to:

Convert light energy into chemical energy

What type of cell signaling involves hormones traveling through the bloodstream?

Endocrine signaling

Which type of receptor activates second messengers like cAMP?

G-protein coupled receptor (GPCR)

What is the role of a second messenger in cell signaling?

Transmits signals inside the cell

What molecule is a second messenger often triggered by GPCRs?

cAMP

Viagra works by increasing levels of which second messenger?

cGMP

Paracrine signaling affects:

Nearby cells

What is autocrine signaling?

A cell signals itself

What phase of the cell cycle involves DNA replication?

S phase

Which of the following best describes mitosis?

2 genetically identical diploid cells

What is the purpose of crossing over in meiosis?

Genetic variation

Which phase of meiosis does independent assortment occur?

Metaphase I

What does Mendel’s Law of Segregation state?

Alleles separate during gamete formation

What ratio results from a monohybrid cross (Aa x Aa)?

3:1

What pattern shows both alleles fully expressed?

Codominance

Which trait is controlled by multiple genes?

Height

A pedigree shows a trait that skips generations. It is likely:

Autosomal recessive

In a dihybrid cross of AaBb x AaBb, what ratio is expected?

9:3:3:1

X-linked traits mostly affect:

Males

Gene mapping is based on:

Recombination Frequency

What is the correct order of the central dogma of molecular biology?

DNA → RNA → Protein

Which enzyme is responsible for adding new nucleotides during DNA replication?

DNA Polymerase

Where does transcription occur in a eukaryotic cell?

Nucleus

What is the role of RNA polymerase?

Build RNA from a DNA template

Which molecule carries genetic information from DNA to ribosomes?

mRNA

Which site in the ribosome is responsible for peptide bond formation?

P site

What does the anticodon on tRNA bind to?

mRNA codon

What modification is not added to mRNA before it leaves the nucleus?

Poly-U tail

Introns are:

Non-coding sequences removed from mRNA

A mutation that introduces a premature stop codon is called:

Nonsense mutation

Inserting or deleting a base shifts the reading frame. This is called:

Frameshift mutation

In the lac operon, what inactivates the repressor?

Lactose

The trp operon is turned off when:

Tryptophan is high

In eukaryotes, acetylation of histones leads to:

Gene activation

Which structure silences genes by tightening DNA?

Methyl groups

What process allows one gene to make different proteins?

Alternative splicing

What is the function of miRNA and siRNA?

Silence gene expression

What is the process of PCR (polymerase chain reaction)?

Amplify DNA segments

What enzyme is used in PCR?

TAq polymerase

Which step in PCR allows primers to bind to DNA?

Annealing

What technique separates DNA fragments by size?

Gel electrophoresis

What type of bond is responsible for water’s surface tension?

Hydrogen

A solution with a pH of 9 is:

Basic

Which organelle is only found in plant cells?

Chloroplast

Which structure controls what enters and leaves the cell?

Cell membrane

Which structure is used for intracellular transport and protein folding?

Rough ER

Prokaryotic cells do not contain:

Nucleus

A non-competitive inhibitor works by:

Binding to an allosteric site

An enzyme’s function depends on its:

Shape

The final electron acceptor in aerobic respiration is:

Oxygen

How many net ATP are produced from glycolysis?

2

In aerobic respiration, CO₂ is released during:

Krebs cycle

Which part of photosynthesis requires light?

Light-dependent reaction

What is the main product of the Calvin cycle?

Glucose

Which pigment absorbs most of the light in plants?

Chlorophyll a

What phase of the cell cycle involves growth and preparation for DNA replication?

G1

When do homologous chromosomes separate?

Anaphase I

What type of inheritance results in a 3:1 phenotypic ratio?

Monohybrid cross

Methylation

Adding methyl groups to cytosine bases.

DNA Methylation

Usually inhibits transcription.

Acetylation of Histones

Causes DNA to unwind and become accessible.

microRNA

Primarily functions to silence mRNA translation.

Dicer

An enzyme that cleaves microRNA.

RISC complex

Involved in RNA silencing.

Alternative Splicing

Allows multiple RNAs from one gene.

Exons

Coding sequences that remain after splicing.

Introns

Non-coding regions removed during splicing.

Ubiquitin

Marks proteins for degradation.

Proteasome

Cellular structure where protein degradation occurs.

ATP

Energy currency required for various biological processes.

Reverse Transcriptase

Enzyme that makes DNA from RNA.

Southern Blot

Technique used to study DNA.

DNA Charge

DNA runs through a gel toward the positive electrode because it is negatively charged.

Nucleotide

The monomer of DNA.

DNA Backbone

Made up of sugars and phosphates.