✅Basic Cells And Tissue Flashcards
What are basic cell functions?
Obtain nutrients and oxygen Perform chemical reactions (for energy) Eliminate carbon dioxide and waste products Synthesise proteins and cell components control exchange of materials Adapt, respond to environmental changes
What is homeostasis?
Homeo-similar Stasus-condition
refers to the existence or maintenance of a stable internal environment
At what level is homeostasis maintained?
The Cellular level
What does it mean if homeostasis is maintained at a higher level?
It reflects combined,coordinated actions of many cells
What components are in the cell interior?
The nucleus
Cytoplasm
- cytosol (gel-like fluid)
-cell organelles (membranous/non-membranous)
What components are in the cell exterior?
Extracellular fluid (interstitial fluid)
What else is the cell membrane know as?
Plasma membrane
Plasmalemma
What is the Cell Membrane?
Its is a phospholipid bilayer made up of proteins, lipids and carbohydrates
What are the 4 functions of the cell membrane?
- Physical Isolation
- regulation of exchange with the environment
- communication between the cell and its environment
- structural support
What is the structure of the nucleus?
- nuclear envelope
- chromatin
- Nucleolus
What is the nuclear envelope?
A barrier that surrounds the nucleus, interrupted by nucleus pores.
What is chromatin?
A network of fibres made of protein and dna. When cells divide, chromatin condenses into chromosomes.
What is the nucleolus?
Coiled structure composed of ribonucleic acid (RNA) and proteins associated with DNA/
What is the function of the nucleus?
Stores and transmits genetic information in the form of DNA to synthesise proteins.
What are Membranous organelles surrounded by?
Lipid membranes.
What are membranous organelles?
endoplasmicreticulum(ER),Golgiapparatus,lysosomes, peroxisomes, mitochondria
What are non-membranous organelles always in contact with?
The cytosol
What are non-membranous organelles?
cytoskeleton,microvilli,centrioles,cilia,ribosomes,proteosomes.
What is the structure of the endoplasmic reticulum (ER)?
network of membranous channels extending throughout the
cytoplasm
– two forms:
•Granular(Rough),withribosomesattached
• Agranular(Smooth)
What are the functions of the ER?
• Rough ER:
– Packaging and transport of proteins secreted by cell or distributed to other cell organelles
• SmoothER:
– Lipid synthesis
– Storage and release of calcium for muscle contraction & other cell activities
What is the structure of Golgi apparatus?
-Stacks of flattened membranes (cisternae) containing chambers
– Found near the nucleus
What is the function of the golgi apparatus?
-Storage, alteration and packaging of secretory products &
lysosomal enzymes
– for transport to plasma membrane
What are the types of Vesicles in the Golgi Apparatus?
– Secretory vesicles–exocytosis
– Membrane renewal vesicles
– Lysosomes
What are the structures of Lysosomes?
Vesicles containing digestive enzymes
What is the function of lysosomes?
Interacellular removal of damaged organelles or pathogens.
What is the structure of Peroxisome?
Vesicles containing degradative enzymes
What is the function of peroxisome?
Catabolism of fats and other organic compounds; neutralisation of toxic compounds generated in the process
What is the mitochondrion otherwise known as?
The powerhouse of the cell.
Describe 6 points about the mitochondrion
• It has a double membrane
• Outer membrane surrounds the organelle
• Inner membrane contains numerous folds (cristae)
• Cristae increase the surface area exposed to the fluid content of matrix
• Metabolic enzymes in the matrix catalyse the reactions that provide energy for cellular functions
• Adenosine Triphosphate (ATP) is produced, which provides energy to the cell (~95%)
What is the structure of ribosomes?
– fixed to the rough ER, or
– as free ribosomes scattered in the cytoplasm
What does each ribosome consist of?
Protein and RNA
What is the function of Ribosomes?
Synthesis of proteins from amino acids using information carried
by RNA molecules, from DNA in the nucleus
Where do proteins synthesised on free ribosomes go?
They pass into the cytosol
Where do proteins synthesised by the Er go?
They go to the Golgi Apparatus
What are three points about Centrioles?
• Direct movement of chromosomes in cell division
• Organise the cytoskeleton
• Cytoplasm surrounding them is the centrosom
What are two points about the cilia?
- anchored by a basal body
- movement of materials (fluids) across cell surface
What is a key point about proteosomes?
Breakdown and recycling of
damaged or abnormal proteins
(contain protein-digesting enzymes called
proteases)
What are two points about the Cytoskeleton?
-Proteins organised in fine filaments or slender tubes
-Provides skeletal strength & flexibilit
What is a key point about the microvilli?
Increase surface area to facilitate absorption
of extracellular materials
Why is plasmalemma said to be selectively permeable?
It allows for free passage of some molecules and restricts the passage of other
What type of ribosome can be found attached to the rough ER?
Fixed ribosomes
