Cell Bio Unit 1 Notes

What is Cell Bio?

the study of the structure, function, and behavior of cells.

What is the cell theory

states that cells are the fundamental units from which all living things exist.

What do all cells have in common?

surrounded by a plasma membrane, (ii) conduct similar biochemical activities, (iii) are capable of reproducing themselves, and (iv) undergo evolution.

What is the membrane most comprised of?

lipids, though it is also studded with proteins that provide for unique membrane functions.

What is “The Central Dogma of Biology’?

whereby the genetic material in deoxyribonucleic acid (DNA) is TRANSCRIBED into ribonucleic acid (RNA) messengers, which are in turn TRANSLATED into proteins, is a common biochemical activity in cells.

Where have cells evolved to?

They occupy nearly every imaginable environmental niche, both on Earth and in the body.

What are the three domains of life?

Bacteria, Archaea, and Eukarya

What are bacteria considered as?

prokaryotes, unicellular organisms¹ that lack a true nucleus.

What are Archae considered as?

prokaryotes, and thus are unicellular organisms with no true nucleus, but they differ from bacteria by having a UNIQUE cell wall structure.

What are prokaryotes like?

Are generally small (e.g. diameter of 2.5µm), have a tough outer cell wall, and reproduce rapidly (e.g. 20 minutes).

What are Eukarya?

They are eukaryotes and have a membrane-enclosed nucleus as well as a traditional suite of other membrane-enclosed organelles².

What are Eukaryotes traditionally like?

They generally larger (e.g. diameter of 25µm; 1000X the volume of prokaryotes), are more elaborately organized, and can exist as either unicellular organisms or within much larger multicellular organisms.

What do membrane bound organelles of eukaryotic cells have?

Specialized structures and functions

What is the nucleus?

It is often the largest organelle, has a double membrane called the nuclear envelope, houses linear strands of genetic material called deoxyribonucleic acid (DNA), and is the site of transcription.

What is the mitochondrion?

It has its own DNA and is thought to have risen by the uptake of a bacterium by an ancestral, predatory archaea over a billion years ago, a process called endosymbiosis.

What is the chloroplast?

It is found in plant cells, has a triple membrane, contains chlorophyll, and is capable of photosynthesis. It also has its own DNA and has an origin similar to that of mitochondria.

What is the ER?What IS THE GOLGI APPARATUS?

     The endoplasmic reticulum (ER) is where the synthesis of membrane materials occurs (lipids, proteins) and is the origin for transport within the endomembrane system of cells. Its membrane can be smooth or it can be rough when studded with ribosomes, which is where translation takes place.

What is the Golgi Apparatus?

The Golgi apparatus is where transport vesicles are repackaged for delivery to different sites within the endomembrane system, including for exocytosis.

What is the lysosome

The lysosome houses hydrolytic enzymes that function in the breakdown and recycling of macromolecules.

What is the vacuole?

The vacuole is the plant cell’s version of the lysosome, though it is typically much larger, and has other diverse functions associated with the maintenance of turgor and in signaling via calcium.

What is the peroxisome?

The perOXIsome houses enzymes that function in the detoxification of reactive oxygen species.

What are the vesicles that pass between the ER, Golgi, Lysosome, and Plasma Membrane important for?

They are important for shipping macromolecules within the endomembrane systems and are membrane-bound.

Cytosol?

The cell is 70% water. Water is found within organelles, and it also found outside them in a part of the cell called the cytosol. The cytosol is so concentrated with macromolecules that it has the consistency of a gel. Free-floating ribosomes in the cytosol are also sites for translation.

What is the cytoskeleton?

Comprised of filamentous proteins that are classified as (i) actin microfilaments, (ii)microtubules, and (iii) intermediate filaments.