The Cell Flashcards
1) Cell Theory 2) Eukaryotic Cells 3) Classification and Structure of Prokaryotic Cells 4) Genetics and Growth 5) Viruses and Subviral Particles (17 cards)
What are the four fundamental tenets of the cell theory?
1- All living things are composed of cells.
2- The cell is the basic functional unit of life.
3- Cells arise only from preexisting cells.
4- Cells carry genetic information in the form of DNA and is passed on from parent to daughter cell.
What are eukaryotic organisms?
Organisms that can be unicellular or multicellular.
They contain eukaryotic cells contain a true nucleus enclosed in a membrane, and numerous membrane-bound organelles.
What do membranes in eukaryotic cells consist of?
Membranes of eukaryotic cells consist of a phospholipid bilayer.
- Its surfaces are hydrophilic, electrostatically interacting with the aqueous environments inside and outside of the cell.
- Its inner portion is hydrophobic, which helps provide a highly selective barrier between the interior of the cell and the external environment.
What is the cytosol and what’s its role?
Each cell has a membrane enclosing a semifluid cytosol in which organelles are suspended.
The cytosol allows for the diffusion of molecules throughout the cell.
Are viruses considered living things and why?
Viruses are not considered living thing because:
- They are acellular.
-They cannot reproduce without this assistance of a host cell. - They may use RNA as their genetic material.
What are the eukaryotic organelles?
- The Nucleus
- The nucleolus
- Mitochondria
- Lysosomes
- The Endoplasmic reticulum
- The Golgi apparatus
- Peroxisomes
Where will proteins synthesized in the RER end up?
These proteins will either:
- Be Secreted into the extracellular environment.
- End up becoming integral proteins in the cell membrane.
- Remain in the RER, GA, or lysosomes.
Where will proteins synthesized in the cytoplasm end up?
These proteins will either end up in:
- The nucleus
- Mitochondria
- Peroxisomes
- Stay in the cytoplasm
What is the secretory pathway?
Proteins that are secreted from the cell, or that become part of the cell membrane follow the SECRETORY PATHWAY.
This is the pathway a protein takes from when its synthesized until it leaves the cell or become part of the cell membrane.
What is the structure of the nucleus like?
Surrounded by the nuclear membrane or envelope, a double-membrane that maintains a nuclear environment separate and distinct from the cytoplasm.
Inside the nucleus, there is the nucleoplasm.
Nuclear pores in the nuclear membrane allow selective two-way exchange of material between the cytoplasm and the nucleolus.
The nucleus contains DNA organized into chromosomes.
What are the functions of the nucleus?
- Stores genetic information (DNA as chromosomes)
- Site of DNA transcription
What is the structure of the nucleolus like?
A subsection of the nucleus. Darker, denser and more compact than the nucleus.
The nucleolus takes up 25% of the nucleus volume.
What is the function of the nucleolus?
Where ribosomal RNA (rRNA) is synthesized.
What is the mitochondrial structure like?
Two layers:
The outer membrane, made up of a lipid bilayer, serves as a barrier between the cytosol and the inner environment of the mitochondrion. It is permeable to small molecules.
The intermembrane space: The space between the outer and inner membranes.
The inner membrane: which is also made up of a lipid bilayer, is arranged into numerous infoldings called cristae, contains the molecules and enzymes of the electron transport chain.
Cristae are highly convoluted structures that increase the surface area available for electron transport chain enzymes.
The mitochondrial matrix: The space inside the inner membrane
They contain their own genes and replicate independently (self-replicate) of the nucleus via binary fission.
(They have their own genome. They have one piece of circular DNA.)
Use a different system of transcription and translation from the nucleus genes.
Have their own unique genetic code.
What are the functions of the mitochondria?
- Involved on ATP (Adenosine triphosphate) production, providing energy, cellular respiration.
- Can trigger apoptosis by releasing mitochondrial enzymes into their cytoplasm.
What are the functions of the lysosomes?
- Contain hydrolytic enzymes that can break down substances ingested by endocytosis and cellular waste products. These enzymes can be released through a process known as autolysis of the cell.
- When these hydrolytic enzymes are released, apoptosis occur.
- Digest various molecules and substances:
1) Autophagy: “Self-eating”: When lysosomes digest molecules that are part of the cell itself or other cells.
2) Crinophagy: When lysosomes digest excess secretory products.
After the lysosomes finish breaking down molecules into their most basic form, it will release into the cytoplasm for them to be reused.
