Cell Biology, Biomolecules, Genetics & Physiology – Comprehensive Review

100 Q&A flashcards covering key topics in cell biology, biomolecules, genetics, cell transport, respiration, photosynthesis, cell cycle, and mutations. Use them to test recall and reinforce understanding for the upcoming exam.

What is the primary role of the centrosome during cell division?

It organizes microtubules and forms the spindle apparatus essential for chromosome separation.

Define an organism.

Any contiguous living system; can be unicellular (1 cell) or multicellular (more than 1 cell).

Which ancient civilization first discovered the microscope?

The Romans.

State the three postulates of modern cell theory.

1) All organisms are made of cells. 2) The cell is the basic unit of life. 3) All cells come from pre-existing cells (Omnis cellula e cellula).

What did the disproved Theory of Spontaneous Generation claim?

That living organisms could arise from non-living matter.

Of what is the cell membrane primarily composed?

A phospholipid bilayer with embedded proteins and carbohydrates.

Why is the cell membrane described as semipermeable?

It allows selective passage of molecules such as O₂ and CO₂ in and out of the cell.

How do microvilli enhance cellular absorption?

By forming finger-like folds that greatly increase surface area.

Where are organelles located within a cell?

Suspended in the cytoplasm.

Name two key metabolic processes that occur in the cytosol.

DNA transcription/replication and glycolysis.

What structural support does the cytoskeleton provide?

It maintains cell shape and anchors/moves organelles.

What is the function of centrioles?

They occur in perpendicular pairs and help separate chromosomes during cell division.

List the three components found in all cells.

Cell membrane, cytoplasm, and DNA.

Which model best explains cell-membrane structure today?

The Fluid Mosaic Model.

What encloses the nucleus?

The nuclear envelope.

What is chromatin?

The combination of DNA and proteins inside the nucleus.

What is produced in the nucleolus?

Ribosomes.

What is the main job of ribosomes?

Protein synthesis.

Differentiate rough ER from smooth ER.

Rough ER has ribosomes and makes proteins; smooth ER lacks ribosomes and makes lipids.

What cellular organelle sorts, modifies, and packages proteins?

The Golgi body (Golgi apparatus).

Which organelle contains hydrolytic enzymes for intracellular digestion?

Lysosome.

Why are mitochondria called the powerhouse of the cell?

They produce ATP through cellular respiration.

What molecule directly supplies energy to most cellular work?

ATP (Adenosine Triphosphate).

Describe flagellar movement.

A whip-like motion that propels the cell (e.g., human sperm).

How does cilium movement differ from flagellum movement?

Cilia beat in power-and-recovery strokes to move fluid or the cell.

What is the main feature distinguishing plant cells from animal cells?

A rigid cell wall made chiefly of cellulose.

Where does photosynthesis occur in plant cells?

In chloroplasts.

What pigment gives plants their green color and captures light energy?

Chlorophyll.

State one function of the large central vacuole in plants.

Temporary storage and maintenance of turgor pressure.

Where in a chloroplast does the Calvin cycle take place?

The stroma.

What are thylakoids?

Membranous sacs in chloroplasts where the light reactions of photosynthesis occur.

What polymer makes fungal cell walls and arthropod exoskeletons rigid?

Chitin.

Name three structures present in plant but not animal cells.

Cell wall, chloroplasts, and large central vacuole.

Give two key differences between eukaryotic and prokaryotic cells.

Eukaryotes have a nucleus and membrane-bound organelles; prokaryotes do not.

Define a monomer.

A repeating molecular unit that serves as a building block for polymers.

What reaction links monomers into polymers while releasing water?

Dehydration reaction (condensation).

Which biomolecule is the body’s quick energy source and what is its monomer?

Carbohydrates; monomer = monosaccharide.

What is a disaccharide?

A carbohydrate composed of two monosaccharides joined by dehydration synthesis.

Name two main functions of polysaccharides.

Energy storage and structural support.

What is the monomer of proteins?

Amino acids (20 standard types).

What bond links amino acids together?

Peptide bond.

Define an enzyme.

A protein that acts as a biological catalyst to speed up reactions.

List the building blocks of fats.

Glycerol and fatty acids.

Which lipid is the main component of cell membranes?

Phospholipid.

What structural feature characterizes steroids?

A carbon skeleton of four fused rings.

What is the function of nucleic acids?

To store and transmit genetic information.

Identify the monomer of nucleic acids.

Nucleotide.

Contrast DNA and RNA in strand number.

DNA is double-stranded; RNA is single-stranded.

What enzyme unwinds DNA during replication?

Helicase.

Define complementary base pairing in DNA.

A pairs with T, and G pairs with C via hydrogen bonds.

What are chromosomes?

Bundles of DNA (genes) that carry hereditary information.

Define a gene.

A short DNA segment that codes for a specific protein or trait.

What does the genome encompass?

The complete set of genetic information in an organism.

What does mRNA do?

Carries DNA instructions from nucleus to ribosomes.

Function of tRNA?

Delivers specific amino acids to the ribosome during protein synthesis.

What is transcription?

Synthesis of an RNA strand from a DNA template.

Define translation.

Process by which ribosomes read mRNA codons to assemble a polypeptide.

What is a codon?

A sequence of three RNA bases that codes for one amino acid.

Define mutation.

A permanent change in a DNA sequence that may alter protein function or traits.

What is an allele?

Different versions of a gene occupying the same locus.

Differentiate genotype from phenotype.

Genotype is an allele combination; phenotype is the observable trait expression.

When is an allele considered dominant?

When its trait appears even if only one copy is present.

What is a heterozygous genotype?

One dominant and one recessive allele (e.g., Tt).

Who is the “Father of Modern Genetics,” and what organism did he study?

Gregor Mendel; pea plants.

State Mendel’s Law of Segregation.

Each individual carries two alleles per gene, but passes only one to offspring.

Explain the Law of Independent Assortment.

Genes on different chromosomes are inherited independently of one another.

What tool predicts offspring genotypes?

A Punnett square.

Give an example of complete dominance.

Red flower allele fully masks white allele, giving red offspring.

Define incomplete dominance.

Heterozygote shows a blended phenotype (e.g., red × white = pink flowers).

What is codominance?

Both alleles are fully expressed in heterozygotes (e.g., red and white patches).

Why are X-linked traits more common in males?

Males have only one X chromosome, so recessive alleles are unmasked.

What are multiple alleles?

More than two possible alleles exist in a population for one gene (e.g., ABO blood).

Define polygenic inheritance.

A trait controlled by two or more genes, producing continuous variation.

Who determines the sex of a human baby?

The father, by contributing either an X or Y chromosome.

What is passive transport?

Movement of substances from high to low concentration without energy input.

Describe simple diffusion.

Direct movement of small nonpolar molecules across the phospholipid bilayer.

What is facilitated diffusion?

Passive movement of larger or polar molecules via membrane transport proteins.

Define osmosis.

Diffusion of water across a semipermeable membrane.

What distinguishes active transport from passive?

Active transport moves substances low → high concentration using ATP.

What is phagocytosis?

Endocytic process in which the cell engulfs large solids (“cell eating”).

What is pinocytosis?

Endocytosis of fluid droplets (“cell drinking”).

Define exocytosis.

Process by which cells expel materials via vesicle fusion with the membrane.

Write the overall equation for cellular respiration (words).

Glucose + Oxygen → Carbon Dioxide + Water + Energy (ATP).

How much ATP is generated by aerobic respiration?

Approximately 36-38 ATP per glucose.

Where does glycolysis occur?

In the cytoplasm of the cell.

Location of the Krebs (citric acid) cycle?

Mitochondrial matrix.

Where is the electron transport chain found?

Inner mitochondrial membrane (cristae).

What by-product causes muscle fatigue during anaerobic respiration?

Lactic acid.

Which fermentation type is used in bread and alcohol production?

Alcoholic fermentation by yeast.

Summarize photosynthesis (words).

Carbon dioxide + Water + Light energy → Glucose + Oxygen.

Which stage of photosynthesis produces ATP and NADPH?

Light-dependent reactions (in the thylakoid).

What is the Calvin cycle?

Light-independent reactions that convert CO₂ to glucose in the stroma.

Define diploid cell.

A cell containing two full sets of chromosomes (46 in humans).

Name the three phases of interphase and give one key event of each.

G1 – cell grows; S – DNA replicates; G2 – prepares for mitosis and repairs DNA.

What is a centromere?

The region connecting two sister chromatids.

Distinguish somatic cells from gametes.

Somatic cells are all body cells (diploid); gametes are sex cells (haploid).

Purpose of mitosis?

To produce two identical diploid daughter cells for growth and repair.

What happens during anaphase of mitosis?

Sister chromatids separate and move toward opposite poles.

Define cytokinesis.

Division of the cytoplasm, forming two separate cells.

Overall result of meiosis?

Four genetically unique haploid gametes from one diploid parent cell.