The Cellular Basis of Life Flashcards

A complete set of 50 Q&A practice flashcards covering cell discovery, cell theory, microscopy, cellular organelles, and transport mechanisms based on chapter 2 lecture notes.

What is the estimated total number of individual cells that compose an average human being?

Around 100 trillion individual cells.

How many cells die in the human body every minute?

Three hundred million cells die every minute.

Who discovered and named cells in 1665 while examining a thin slice of cork?

English scientist Robert Hooke.

What term did Antonie van Leeuwenhoek give to the microscopic single-celled organisms he observed in pond water in 1674?

Animalcules.

Which scientist is recognized as the Father of Microscopy?

Antonie van Leeuwenhoek.

Which Scottish botanist discovered and named the nucleus inside orchid cells in 1831?

Robert Brown.

What conclusion did German botanist Matthias Jakob Schleiden reach in 1838 regarding plants?

He concluded that all plant parts are made of cells.

What was the main scientific conclusion made by German physiologist and zoologist Theodor Schwann in 1839?

He concluded that all animal tissues are composed of cells.

What Latin phrase meaning cells arise from pre-existing cells was introduced by Rudolf Virchow in 1855?

Omnis cellula e cellula.

How did Francesco Redi challenge the theory of spontaneous generation in 1668?

He conducted an experiment with decaying meat to show that maggots came from flies rather than spontaneously generating from rotting meat.

Why did Lazzaro Spallanzani suspect that John Turberville Needham's 1745 experiment erroneously claimed victory for spontaneous generation?

Spallanzani suspected that Needham had not boiled the broth long enough to kill all microbes.

What famous experimental setup did Louis Pasteur use in 1861 to prove that microorganisms come from pre-existing environmental microbes?

The swan-neck flask experiment.

Who proposed the first two statements of the Classical Cell Theory between 1838 and 1839?

Matthias Jakob Schleiden and Theodor Schwann.

Who are widely credited with inventing the first compound microscope around 1590?

Dutch eyeglass makers Zacharias Janssen and his father, Hans Janssen.

What was the maximum magnification capability of the early compound microscope created by Zacharias and Hans Janssen?

Approximately $9\times$.

What type of microscope and maximum magnification did Robert Hooke use to discover cells in 1665?

An improved compound microscope with 3 lenses and a maximum magnification of approximately $50\times$.

What maximum magnification was achieved by Antonie van Leeuwenhoek's advanced simple microscope in 1674?

Approximately $270\times$.

What is the standard magnification range of a modern light microscope?

$400\times$ to $1000\times$.

How is the total magnification of a light microscope calculated?

By multiplying the power of the objective lens by the power of the eyepiece lens.

What component in a confocal microscope blocks out-of-focus light to ensure image sharpness from a precise depth?

A tiny pinhole filter.

Which electron microscope type scans a specimen with a focused electron beam to generate a detailed 3D image of its surface?

Scanning Electron Microscope (SEM).

Why is the Transmission Electron Microscope (TEM) the preferred instrument for visualizing the internal structures of cells?

Because it uses a beam of electrons to see through a specimen, providing ultra-high-resolution imaging of internal cellular structures, molecules, and individual atoms.

Which cell wall constituent is present in Domain Bacteria but absent in Domain Archaea?

Peptidoglycan.

What three environmental groups are highlighted under Domain Archaea?

Methanogens, extreme halophiles, and extreme thermophiles.

What structural cell junctions are unique to plant cells versus animal cells?

Plant cells possess plasmodesmata, whereas animal cells possess gap junctions.

What primary energy storage molecule is used in plant cells compared to animal cells?

Plant cells store energy as starch, whereas animal cells store energy as glycogen.

How thick is the thin barrier formed by the cell's plasma membrane?

$8\text{ nm}$ thick.

Which chemical portion of a phospholipid is polar and water-soluble?

The phosphate head.

What types of molecules are capable of crossing the phospholipid bilayer directly via passive diffusion at significant rates?

Small, relatively hydrophobic molecules.

Which specific organic molecules are transported across the cell membrane by carrier proteins during facilitated diffusion?

Glucose and amino acids.

How is the net direction of osmosis determined when comparing two solutions?

It is determined by total solute concentrations, with water moving from a hypotonic solution (less solute, more water) to a hypertonic solution (more solute, less water).

What process uses a protein pump and ATP to move solutes against a concentration gradient?

Active transport.

What is the difference between phagocytosis and pinocytosis in endocytosis?

Phagocytosis transports large particulate matter such as bacteria or dead cells, whereas pinocytosis transports liquids and dissolved small particles.

What major metabolic pathways occur directly within the cytoplasm?

Glycolysis, gluconeogenesis, and the biosynthesis of sugars, fatty acids, and amino acids.

How many mitochondria can typically be present in a single cell?

Up to 300 to 800 per cell.

According to endosymbiotic theory, mitochondria developed from which group of free-living bacteria?

Proteobacteria.

What structure in the outer membrane of a mitochondrion allows small molecular substances to freely pass?

Channel proteins (hole proteins).

Where are elementary particles, or ATP synthase, located within a mitochondrion?

In the inner membrane.

In which specific location of the mitochondrion does the Krebs cycle take place?

In the mitochondrial matrix.

What fluid-filled interior space is enclosed by the double membrane of a chloroplast?

The stroma.

Which internal structure of the nucleus serves as the site for ribosome assembly?

The nucleolus.

What two key genetic processes occur exclusively inside the cell nucleus?

Replication (DNA copying itself) and transcription (DNA being copied into RNA).

What protein modification process occurs in the Rough Endoplasmic Reticulum when sugar groups are attached to polypeptide chains?

Glycosylation.

What are five major metabolic roles performed by the Smooth Endoplasmic Reticulum (SER)?

Synthesis of steroids and lipids, carbohydrate metabolism, regulation of calcium ions, drug detoxification, and metabolism of steroids.

What process do non-membrane-bound ribosomes perform to convert mRNA genetic code into protein chains?

Translation.

What organelle consists of stacked flattened pouches called cisternae and acts as the shipping and receiving center of the cell?

The Golgi apparatus.

How does the plant central vacuole help maintain the structural upright stance of a plant?

It fills with water and exerts outward turgor pressure against the rigid cell wall to prevent wilting.

What paired barrel-shaped organelles near the nuclear envelope organize microtubules and grow spindle fibers during cell division?

Centrioles.

What acidic pH range is maintained inside a lysosome to optimize hydrolytic enzyme activity?

A pH of about 4.5 to 5.0.

Which enzyme inside peroxisomes catalyzes the breakdown of dangerous hydrogen peroxide into water and oxygen gas ($2H_2O_2 \rightarrow 2H_2O + O_2$)?

Catalase.