lecture 8: cell structure Flashcards
What are the 9 components of an eukaryotic cell?
- Nucleus
- Ribosomes
- Cytoskeleton
- Mitochondrion
- Chloroplast
- Lysosome
- Vacuole
- Endomembrane System
- Cell Wall
What are the 3 functions of the nucleus?
- Information storage: house most of organism’s genome in chromosomes
- Information processing: regulate gene expression
- Ribosome assembly: done within nucleolus
Nucleus structure?
- Nuclear envelope
- Chromosomes
- Nucleolus
- Nuclear matrix (cytoskeleton of nucleus)
What is the nuclear envelope made of?
- Double membrane: each consists of a lipid bylayer
- Large pores (circle of proteins) that regulate entry/exit of molecules
What is the nucleolus?
- Distinct region located in nucleus
2. Site of ribosomal RNA (rRNA) synthesis & ribosome assembly
What is a ribosome’s function?
To carry out protein synthesis
What are the 2 locations in which ribosomes carry out protein synthesis?
- Free: in cytosol
2. Bound: on the outside of rough endoplasmic reticulum (rER)
Ribosomes structure?
- Particles made of ribosomal RNA + ribosomal protein
- Non-membranous (not strictly considered organelles)
- Separeated in a large and a smal subunit, both containing special RNA molecules and protein
What is the cytoskeleton?
- Estensive network of protein fibers extending throughout cytoplasm
- Dynamic system, constantly remodeled
What are the 2 functions of the cytoskeleton?
- Cell shape and support: gives distinctive shape + high level of internal organization (structure provides support & protection)
- Movement: intereact with motor proteins to move inside of cell + cell itself
How do mivrovillus (microvilli) maintain their structure and shape?
With the help of the cytoskeleton (plasma membrane is too liquid to held them up)
What are 3 examples of movement within the cell
(by cytoskeleton and motor proteins)?
- Chromosome movement during cell division
- Vesicle movement to transport cargo within the cell
- Flow of cytosol and organelles around plant cell
What are 3 examples of movement of the cell
(by cytoskeleton and motor proteins)?
- Cilia: small hairs to move cell in a “swimming” matter
- Flagellum: small tail
- Amoeboid movement: like a “blob”, moving by changing cell shape
What are the 2 organelles involved in energy transformation?
- Mitochondria (plants and animals)
2. Chloroplast (only plants)
Mitochondria function?
- Sites of cellular respiration: Sugar +O2 —> CO2 + H2O + ATP (provide energy source)
Mitochondria structure?
- Double membrane: smoother outer memebrane + inner membrane —> 2 compartments
- Fold of inner membrane = large surface area —> machinery for cellular respiration
What is ATP?
Adenosine triphosphate: the energy currency in cells
- Energy is released when ATP is hydrolyzed (reacts with water)
Chloroplasts function?
- Sites of photosynthesis: CO2 + H2O + Sunlight —> Sugar + O2
Chloroplast structure?
- Member of a family of organelles called plastids (specialized in photosynthesis)
- Contain pigments + other enzymes and molecules that function in photosynthesis
- Double membrane + 3rd internal (thylakoid) membrane that forms internal network —> 3 compartments
- Machinery for photosynthesis = imbedded in thylakoid membrane