Cell Biology and General Chemistry Review

Comprehensive practice flashcards covering cell organelles, microscopy, scientific method, and chemistry of life from Campbell Essential Biology Chapter 4 and BIOL 101 notes.

What are the two foundational assertions of cell theory?

All living things are composed of cells, and all cells come from pre-existing cells.

Which type of micrograph provides a detailed view of surface features, and how must the specimen be prepared?

A Scanning Electron Micrograph (SEM), and specimens must be killed.

Into which three major domains is all life classified, and which cell types compose them?

Domains Bacteria and Archaea consist of prokaryotic cells, while Domain Eukarya consists of eukaryotic cells.

In a prokaryotic cell, where is the single circular bacterial chromosome located?

In the nucleoid region.

What is the primary structural feature that distinguishes eukaryotic cells from prokaryotic cells?

Eukaryotic cells are partitioned by internal membranes into distinct organelles.

Why is the plasma membrane described as a "fluid mosaic"?

It is fluid because molecules can move freely past one another, and a mosaic because of the diversity of proteins embedded within the phospholipid bilayer.

What structural material forms plant cell walls, and what sticky coat do animal cells secrete in place of a cell wall?

Plant cell walls are made of cellulose fibers, while animal cells secrete an extracellular matrix.

What is the main function of the nucleolus within the eukaryotic nucleus?

It is the prominent site where the components of ribosomes are made.

What molecule carries genetic instructions from nuclear DNA into the cytoplasm for ribosome binding and protein synthesis?

Messenger RNA (mRNA).

How do rough ER and smooth ER differ structurally and functionally?

Rough ER is studded with ribosomes and manufactures/modifies proteins; smooth ER lacks ribosomes, synthesizes lipids (including steroids), and detoxifies circulating drugs.

What is the primary role of the Golgi apparatus in cell manufacturing?

It receives, refines, stores, and distributes chemical products transferred from the ER.

What cellular organelle contains digestive enzymes to break down food particles and recycle damaged organelles in animal cells?

Lysosome.

What is the function of a contractile vacuole in freshwater protists such as Paramecium?

It pumps out excess water that flows into the cell from the surrounding environment.

What are the internal fluid and disk-shaped membrane structures within a chloroplast called?

The fluid is the stroma, and the disk-shaped structures are thylakoids (stacked into granum).

What metabolic process occurs in mitochondria, and what molecule does it produce as direct cellular fuel?

Cellular respiration occurs in mitochondria, producing ATP.

What structural features support the endosymbiont theory for the evolution of mitochondria and chloroplasts?

Both contain single circular DNA chromosomes resembling prokaryotic chromosomes, possess their own ribosomes, and reproduce by pinching in two.

How do microtubules differ in structure from microfilaments and intermediate filaments?

Microtubules are hollow protein tubes, whereas microfilaments and intermediate filaments are thinner, solid fibers.

What are the core steps of the scientific method presented in the course notes?

Observation, Question, Hypothesis, Experiment, Conclusion.

How did Louis Pasteur test and reject the hypothesis of "spontaneous generation"?

He showed that sterile broth in swan-neck flasks remained free of life unless dust containing outside microbes was introduced into the liquid.

What are the 8 characteristics of living things listed in the notes?

1. Assimilate energy; 2. Respond to their environment; 3. Maintain a relatively constant internal environment; 4. Reproduce; 5. Possess an inherited information base encoded in DNA; 6. Are composed of one or more cells; 7. Are evolved from other living things; 8. Are highly organized compared to inanimate objects.

In the hierarchical organization of life, what level exists directly between tissue and organ system?

Organ.

What is biology's chief unifying principle, and how is it defined?

Evolution, defined as the gradual modification of populations of living things over time.

In controlled scientific experiments, how does the independent variable differ from the dependent variable?

The independent variable is manipulated by researchers as a potential cause, while the dependent variable is the measured effect or output used to judge outcomes.

What defines a double-blind scientific study?

An experiment in which neither the study participants nor the researchers know which individuals are in the control group or experimental group.

What were the results of A.V. Hill's 1929 experiment on isolated frog muscles?

When lactic acid could not diffuse away, muscle performance declined; when lactic acid was allowed to diffuse away, the muscle worked twice as long.

What distinguishes atomic number from atomic mass?

Atomic number represents the number of protons unique to an element, while atomic mass reflects the combined weight of protons and neutrons.

How do isotopes of the same element differ from one another?

They contain the same number of protons but different numbers of neutrons.

How do covalent bonds differ structurally from ionic bonds?

Covalent bonds share electrons between atoms, whereas ionic bonds form from electrostatic attraction after complete electron transfer.

What causes a covalent bond to be polar rather than nonpolar?

Electronegativity differences between bonded atoms, causing shared electrons to be pulled unequally toward one atom.

Why is ice less dense than liquid water, allowing it to float?

In ice, stable hydrogen bonds hold water molecules at fixed distances in a crystalline lattice spread further apart than in dense liquid water.

How do acids and bases alter hydrogen ion concentrations in aqueous solutions?

Acids yield hydrogen ions ($\text{H}^+$) to increase acidity, while bases accept hydrogen ions ($\text{H}^+$) or release hydroxide ions ($\text{OH}^-$) to reduce acidity.

What are the two most abundant elements in the human body by percentage mass?

Oxygen ($65\%$) and carbon ($18\%$).

What are the four major functional groups listed in Table 3.1 and where are they found?

Carboxyl ($\text{--COOH}$; fatty acids, amino acids), Hydroxyl ($\text{--OH}$; alcohols, carbohydrates), Amino ($\text{--NH}_2$; amino acids), and Phosphate ($\text{--PO}_4$; DNA, ATP).

What polymer biological molecules are formed by monosaccharides, amino acids, and nucleotides?

Monosaccharides form polysaccharides; amino acids form polypeptides or proteins; nucleotides form nucleic acids.

Why are unsaturated fatty acids typically liquid oils rather than solid fats at room temperature?

Double carbon bonds create "kinks" in the hydrocarbon chain that prevent molecules from packing tightly together.

How do phospholipids arrange themselves when exposed to water?

Their hydrophilic polar heads face outward toward water, while their hydrophobic nonpolar fatty acid tails cluster together away from water.

What functional components are bonded to the central carbon in all amino acids?

An amino group ($\text{--NH}_2$), a carboxyl group ($\text{--COOH}$), a hydrogen atom, and a variable side chain ($\text{R}$ group).

What defines the four levels of protein structure?

Primary = amino acid sequence; Secondary = localized motifs like alpha helices and beta pleated sheets; Tertiary = overall 3D folded shape; Quaternary = assembly of two or more polypeptide chains.

What sugar and nitrogenous base differences distinguish DNA from RNA?

DNA contains deoxyribose sugar and thymine, whereas RNA contains ribose sugar and uracil.