Chapter 3 Cellular level of organization Flashcards
What is the plasma membrane?
Forms the cells outer boundary, and separates the cell’s internal environment form the outside environment
What role does the plasma membrane play?
selective barrier which plays a vital role in cellular communication
What is the cytoplasm?
All the cellular contents between the plasma membrane and the nucleus
What is the cytosol?
The fluid portion of a cell, mostly, water
What are organelles?
Subcellular structures having characteristic shapes and specific functions
What is the nucleus?
Large organelle that contains DNA , each of which consists of a single molecule of DNA and associated proteins
A chromosome contains thousands of hereditary units called what?
Genes
What is the fluid mosaic model?
The arrangement of molecules within the membrane resembles a sea of lipids containing many types of proteins
What acts as barrier to certain substance in a plasma membrane?
Lipids
Proteins act as what to certain molecules and ions
Gatekeepers
What is the lipid bilayer made up of?
1.Phospholipids
2. cholesterol
3. Glycolipids
What are integral proteins?
Extend into or through the lipid layer
What are transmembrane proteins?
Most integral proteins, span the entire lipid bilayer
What are peripheral proteins?
Attached to the inner or outer surface of the membrane, do not extend through it
Is the cell membrane permeable?
It is depending on the substance
What is the lipid bilayer permeable to?
- Oxygen
- Carbon dioxide
- water
- Steroids
What is the glucose bilayer not permeable to?
Glucose
What does the transmembrane proteins do?
Act as channels and transporters to assist the entrance of certain substances. For example, glucose and ions
What is the cytoskeleton of a cell?
Network of protein filaments throughout the cytosol, which provides structural support for the cell
What are different types of cytoskeleton?
- Microfilaments
- Intermediate filaments
- Microtubules
What is the centrosome?
located near the nucleus, consists of two centrioles and pericentriolar material
What are cilia?
Short hair like projections from the cell surface, move fluids along a cell surface
What are flagella?
Longer than cilia, move an entire cell; an example is the sperm cells tail
What are ribosomes?
Sites of protein synthesis
What is the endoplasmic reticulum?
Network of membranes in the shape of flattened sacs or tubules
What is a rough endoplasmic reticulum?
Connected to the nuclear envelope, and series of flattened sacs, surface is studded with ribosomes, produces various proteins
What are smooth Endoplasmic reticulum
A network or membrane tubules, does not have ribosomes, synthesizes fatty acids and steroids, detoxifies certain drugs
What is the Golgi complex?
Consists of 3-20 flattened, membranous sacs called cisternae. which modify, sort, and package proteins for transport to different destinations. The proteins are transported by various vesicles
What are lysosomes?
Vesicles that form from the Golgi complex, contain powerful digestive enzymes
What are mitochondria?
Powerhouse of the cell, they generate ATP
Where are mitochondria more prevalent?
Physiologically active cells like
1. muscles
2. liver
3. kidneys
What are cristae?
Series of folds of the inner membrane?
What are matrix?
Large central fluid filled cavities
What is the nuclear envelope?
A double membrane that separates the nucleus from the cytoplasm
What are nuclear pores?
Numerous openings in the nuclear envelope, control movement of substance between nucleus and cytoplasm
What is the nucleolus?
Spherical body that produces ribosomes
What are genes?
The cells hereditary units, controls activities and structures of the cell
What are chromosomes?
Long molecules of DNA combined with protein molecules
What is passive processes?
Substances move across cell membranes without the input of any energy; use the kinetic energy of individual molecules of ions
What are active processes?
When cells uses energy, primarily from the breakdown of ATP, to move a substance across the membrane. IE against a concentration gradient
What are the four type of passive transport?
- simple diffusion
- Facilitated diffusion
- Osmosis
- filtration
What is osmosis?
Net movement of water through a selectively permeable membrane from an area of high concentration of water (lower concertation of solutes) to one of lower concentration of water.
What are two ways to get through the plasma membrane?
- Through lipid bilayer by simple diffusion
- Through aquaporins, integral membrane proteins
What is tonicity?
A measure of the solutions ability to change the volume of cells by altering their water content
What is hyportonic?
A solution that has a lower concentration of solutes than the cytosol inside the cell
What is Hypertonic?
A solution has a higher concentration of solutes than does the cytosol inside the cell
What is filtration?
Movement of water and dissolved substance from an area of high pressure to an area of low pressure
What is an example of filtration in the body?
capillary beds in the kidneys moving small ions from blood stream and leaving larger protein molecules in bloodstream.
What is active transport?
Movement of molecules across a membrane from area of low concentration to area of high concentration
What does active transport require?
ATP
What are three types of active transport?
- Active transport pumps
- Endocytosis
- exocytosis
What is an example of active transport pumps?
Sodium potassium pumps
What is a vesicle?
A small spherical sac formed by budding off from a membrane
What is endocytosis?
When materials move into a cell in a vesicle formed from the plasma membrane
What are three types of endocytosis?
- receptor mediated endocytosis
- Phagocytosis
- Bulk phase endocytosis
What is exocytosis?
Vesicles fuse with the plasma membrane, releasing their contents into the extracellular fluid
