Cell theory Flashcards
Name a few of the Nucleus functions
Site of DNA replication, majority of DNA is held, site of gene transcription
Large macromolecules (ex proteins) imported from the cytoplasm needs a …. to be able to pass into the nucleus.
special signal
What is Chromatin?
DNA combined with protein that creates a fibrous complex
What is Chromosomes?
Chromatin exists in long thin threads which are called chromosomes
What are the two different endoplasmic reticulums?
Rough endoplasmic reticulum (RER)
Smooth endoplasmic reticulum (SER)
Where is newly synthesised proteins transported?
Into RER lumen
What are the 4 functions of ribosomes?
- Chemical modification of small molecules taken into the cell that might be toxic
- Site for glycogen degradation in animal cell
- Site for lipid & steroid synthesis
- Calcium storage
In which cells do you find 70S ribosomes?
plant cells
The Golgi apparatus often contains two components, which?
Cisternae & small membrane-enclosed vesicles
What are the Golgi apparatus functions?
- Receives protein-containing vesicles from RER
- Modifies, concentrates, packages and sorts proteins —> transport to cellular or extracellular destinations
- Adds carbohydrates to proteins & modifies carbohydrates attached to proteins from RER
- Synthesizes some polysaccharides for plant cell wall
The Cistenae has three functionally regions, what are they called?
Cis-region, Trans-region & Medial-region
What is the Mitochondria usually called?
The energy producer
What can you find in the mitochondria matrix?
Enzymes, DNA & ribosomes
What is the function of the Peroxisomes?
Accumulate toxic peroxides resulting from other cellular activities and safety degrade them
What is the function of the cytoskeleton?
- Support the cell and maintain its shape
- Hold organelles in position within the cell
- Move organelles around within the cell
- Involved in the movements of the cytoplasm
- interacts with extracellular structures
The cytoskeleton contains of three components, describe these.
- Microfilaments - consists of actin monomers bundled together
- Intermediate filaments - consists of fibrous proteins organised in tough, rope-like structures. Two major functions; anchor cell structures in place & resist tension.
- Microtubules - long, hollow, unbranched cylinders.
Two major functions: form a rigid internal skeleton for some cells & act as a framework which motor proteins can move structures within cell
In what cells can you find lysosomes?
animal cells
Lysosomes contain digestive enzymes. What do they do?
They degrade proteins, polysaccharides, nucleic acids & lipids
In what cells can you find Vacoules?
In plant cells
The Vacuole has 6 functions, which are they?
- Storage (sugars, ions, organic acids)
- Digestion
- pH & ionic homeostasis: controls uptake and release of protons (H+) & ions to control the cytosol and activity of cytosolic enzymes
- Defence: accumulate toxic compounds to discourage insect and animal herbivores & to kill the pathogenic microbes
- Protected from toxic compounds: some crops (ex Hemp) used to absorb heavy metals, concentrates in the vacuole
- Pigmentation: contain different anthocyanin (attract pollinators and seed dispersers), screen out harmful UV & high light
What is Cellulose?
Repeating monomers of glucose (beta 1.4 glycosidic linkage)
In plant cells you find cell walls. These walls consists of primary & secondary cell wall. Describe these.
Primary cell wall - consists of cellulose fibrils joined by polysaccharides and structural proteins
Secondary cell wall (mostly in trees) - strengthening function (lignin), help in water transport (xylem cells)
Plant cells are connected by narrow channels, what are they called?
Plasmodesmata
What is the function of the plasmodesmata?
Provide a pathway for the transport of different substances –> sugars, amino acids, hormones etc.
