Cell Biology CH6

This set of flashcards covers key concepts and terminology from the lecture notes on cell biology, focusing on cell structure, function, and different types of microscopy.

What is the basic unit of structure and function in an organism?

The cell.

What tool is used to visualize cells?

Microscopes.

What does magnification refer to in microscopy?

The ratio of an object's image size to its real size.

What does resolution refer to in microscopy?

the measure of the clarity of the image, or the minimum distance of two distinguishable points

What two types of microscopy were discussed in the lecture?

Light Microscopy and Electron Microscopy.

How much can light microscopes effectively magnify specimens?

About 1,000 times the size of the actual specimen.

What is the resolution of standard light microscopy

It is too low to study most organelles, the membrane-enclosed structures in eukaryotic cells

What are the two types of electron microscopes?

Scanning Electron Microscopes (SEMs) and Transmission Electron Microscopes (TEMs).

What do scanning electron microscopes provide?

3-D images of a specimen's surface of electrons.

What does transmission electron microscope provide?

Focus a beam of electrons through a specimen

What is the basic structural and functional unit of every organism is one of two types of cells?

Prokaryotic or Eukaryotic

What characterizes prokaryotic cells?

They have no nucleus and no membrane-bound organelles.

What characterizes eukaryotic cells?

Nucleus with a double membrane, and membrane bound organalles

Which cell is larger eukaryotic or prokaryotic?

Eukaryotic cells are generally much larger than prokaryotic cells

Which domains consist of prokaryotic cells?

Bacteria and Archaea.

What are the basic features common to all cells?

Plasma membrane, cytosol, chromosomes, and ribosomes.

What is the role of the plasma membrane?

It is a selective barrier allowing passage of substances.

Where is most of the DNA in a eukaryotic cell housed?

In the nucleus and carried by ribosomes.

What does ribosomes uses from the DNA?

It uses information from the DNA to make proteins, mature ribosomes found in cytosol.

What does the nucleus contain?

The nucleus contains most of the cell’s genes and is usually the most conspicuous organelle

What does the nuclear envelope?

The nuclear envelope encloses the nucleus, separating it from the cytoplasm

What type of membrane is a nuclear envelope?

A double membrane; each membrane consists of a lipid bilayer interspersed with proteins

What regulates the entry and exit of molecules from the nucleus?

Pores lined with a pore complex.

What do chromosomes contain?

Each chromosome contains one DNA molecule associated with proteins.

What is a chromosome referred to in a non-condensed form?

Chromatin

What do chromatin condense to?

Chromatin condenses to form discrete chromosomes as a cell prepares to divide

What structure contains ribosomal RNA synthesis?

Nucleolus.

What is a Ribosome?

Ribosomes are complexes made of ribosomal RNA and protein

What two locations do ribosomes build protein?

In the cytosol (free ribosomes) and On the outside of the endoplasmic reticulum or the nuclear envelope (bound ribosomes)

What system regulates protein traffic in the cell?

The endomembrane system.

What are the main components of the endomembrane system?

Nuclear envelope, endoplasmic reticulum, Golgi apparatus, lysosomes, vacuoles, and plasma membrane.

What is the endoplasmic reticulum (ER)?

It accounts for more than half of the total membrane in many eukaryotic cells

What is the function of the smooth endoplasmic reticulum (ER)?

Synthesizes lipids, detoxifies drugs and poisons, stores calcium ions.

What does the rough endoplasmic reticulum (ER) do?

Secretes glycoproteins and distributes transport vesicles.

What is the Golgi apparatus?

The Golgi apparatus consists of flattened membranous sacs called cisternae

Functions of Golgi apparatus?

Modifies products of the ER, manufactures certain macromolecules, sorts and packages materials into transport vesicle

What is a lysosome?

A membranous sac of hydrolytic enzymes that digests macromolecules.

Where do lysosomal enzymes work?

Lysosomal enzymes work best in the acidic environment inside the lysosome

What are vacuoles used for in cells?

They perform various functions such as storage and maintenance.

What roles do mitochondria play in cells?

They are sites of cellular respiration and ATP generation.

What similarities do mitochondria and chloroplasts share with bacteria?

They are enveloped by a double membrane and contain circular DNA.

What is the function of chloroplasts?

They are sites of photosynthesis in plants and algae.

What are peroxisomes?

Specialized metabolic compartments that remove hydrogen atoms and form hydrogen peroxide.

What are the three main types of cytoskeleton fibers?

Microtubules, microfilaments, and intermediate filaments.

What is the primary role of microtubules?

To shape the cell and guide the movement of organelles.

What is the function of intermediate filaments?

To support cell shape and fix organelles in place.

What are plant cell walls primarily made of?

Cellulose.

What is the extracellular matrix (ECM)?

An elaborate network that animal cells are covered with, made of glycoproteins.

What are plasmodesmata?

Channels that connect plant cells.

What do tight junctions do in animal cells?

They prevent leakage of extracellular fluid.

What are gap junctions?

Communicating junctions that provide cytoplasmic channels between adjacent cells.