Chapter 4: Cell Structure Flashcards

Flashcards reviewing key concepts in Cell Structure including protein folding, cell hierarchy, organelles, and prokaryotic vs eukaryotic features.

What causes denaturation in a protein, and what is its result?

Denaturation is caused by changes in conditions like pH or temperature that break chemical interactions, altering the protein's structure and leading to a change in its function.

What is an example of irreversible protein denaturation involving temperature?

Heating an egg to extreme temperatures causes egg albumin protein to irreversibly denature, changing from liquid to solid.

To what energy state does a protein fold to attain maximum stability?

A protein continues to fold until it reaches its lowest energy state, which is its most stable state.

Which disease-associated proteins are implicated in Alzheimer's Disease according to the lecture?

Amyloid $\beta$ and Tau protein.

What three detrimental outcomes can result from disease-associated protein misfolding?

Gain of toxic activity, protein aggregation, and loss of biological function.

What are the four essential cell processes described in the lecture?

Nutrient uptake, waste removal, energy use, and reproduction.

What is the structural hierarchy of multicellular organisms from the simplest to the most complex level?

Cells combine to form tissues, tissues combine to form organs, organs form organ systems, and organ systems form the organism.

How is magnification distinguished from resolving power in microscopy?

Magnification is the enlargement of an object in appearance, whereas resolving power is the ability to distinguish two adjacent structures as separate.

What four components are shared by all cells?

An enclosing plasma membrane, cytoplasm made of cytosol, DNA, and ribosomes.

What does the word prokaryote mean, and which domains does it include?

Prokaryote comes from the Greek word for "pre-nucleus" and includes Bacteria and Archaea.

In prokaryotic cells, where is the chromosomal DNA localized?

Chromosomal DNA is localized in a region called the nucleoid.

What molecule makes up the cell wall of most prokaryotes?

Peptidoglycan.

What is the primary function of the cell plasma membrane?

It controls the passage of organic molecules, ions, water, and oxygen into and out of the cell.

What percentage of cytoplasm is composed of water?

$70\text{--}80\%$ of the cytoplasm is water.

What is the function of the nucleolus inside the eukaryotic nucleus?

It is the region inside the nucleus where ribosomes are assembled from RNA and proteins.

How do bacterial ribosomes differ in size from eukaryotic ribosomes?

Bacterial ribosomes are $70\text{S}$ ($30\text{S} + 50\text{S}$ subunits), whereas eukaryotic ribosomes are $80\text{S}$ ($40\text{S} + 60\text{S}$ subunits).

Why is the mitochondrion referred to as the powerhouse of the cell?

Because it converts stored energy from macromolecule molecular bonds into ATP.

What metabolic functions do peroxisomes perform?

They break down fatty acids and amino acids, detoxify poisons, and act as free radical scavengers.

Which two organelles are present in animal cells but absent in plant cells?

Centrosomes and lysosomes.

Which structures are found in plant cells but not in animal cells?

A rigid cell wall, chloroplasts (and other specialized plastids), and a large central vacuole.

How does the plant cell wall differ structurally from prokaryotic cell walls?

Plant cell walls are made of cellulose, whereas prokaryotic cell walls are primarily made of peptidoglycan.

In chloroplasts, what is a granum and what process occurs there?

A granum (plural: grana) is a stack of interconnected, fluid-filled thylakoids where photosynthesis takes place.

What is the function of the central vacuole in plant cells?

It regulates water concentration under changing environmental conditions and contributes to cell expansion.

Which structures comprise the endomembrane system in eukaryotic cells?

The nuclear envelope, lysosomes, vesicles, endoplasmic reticulum, Golgi apparatus, and plasma membrane.

What are the primary functions of the rough ER and smooth ER, and what fraction of cellular proteins mature in the rough ER?

The rough ER modifies proteins (maturing nearly $\frac{1}{3}$ of cellular proteins), while the smooth ER synthesizes lipids.

What are the receiving and maturing faces of the Golgi apparatus called?

The receiving side is the cis face, and the opposite maturing side is the trans face.

What structural and functional differences distinguish cilia from flagella?

Flagella are long, hair-like structures enabling whole-cell movement, while cilia are shorter, cover the cell surface, and move whole cells or move substances along the cell surface.