Cellular Level of Organization Flashcards
Function of cell membrane?
- Protects cell
- Regulates materials entering/leaving cell
Define:
Phospholipid bilayer
Two adjacent layers of phospholipids arranged tail to tail
The polar phosphate heads are attracted to water in ICF and ECF while the nonpolar tails keep fluid from entering the intermembrane space.
What are the two types of integral proteins?
- Receptor proteins
- Glycoproteins
Function of a receptor protein?
- Selectively binds molecules externally to induce internal changes
- Identify cell for recognition by other cells
Define:
Glycoprotein
Protein embedded in cell membrane that has carbohydrate attached, extends into extracellular matrix
Function of glycoprotein?
Help signal cell identity
The structure of the lipid bilayer only allows what substance to pass via simple diffusion?
Small non-polar substances
Define:
Diffusion
Movement of particles from area of high concentration to area of low concentration
Define:
Osmosis
Diffusion of water
Define:
Sodium-potassium pump
Type of active transport found in membranes of nerve cells
Define:
Endocytosis
Ingests material by wrapping it with part of cell membrane and pinching it off to form intracellular vesicle
What are the three types of endocytosis?
- Phagocytosis
- Pinocytosis
- Receptor-mediated endocytosis
Define:
Exocytosis
Vesicles inside cell fuse with cell membrane, releasing contents of vesicle outside of the cell
Function of rough endoplasmic reticulum (ER)?
- Protein synthesis
Function of smooth endoplasmic reticulum (ER)?
- stores and regulates calcium
- metabolizes carbohydrates
- breaks down toxins
Function of Golgi apparatus?
Sorts, modifies, and ships products from rough ER and produces lysosomes
Function of lysosomes?
Break down and digest material
Function of mitochondria?
Convert stored energy (glucose) into ATP
Function of peroxisomes?
- Lipid metabolism
- Chemical detoxification
- Hydrogen peroxide production
Function of cytoskeleton?
- Maintains structure
- Cell motility
- Cell reproduction
- Transportation of materials within cell
What are the three types of fibrous proteins that make up the cytoskeleton?
- Microfilaments
- Intermediate filaments
- Microtubules
Function of microtubules?
Maintain cell shape and structure
Function of cilia?
Move constantly
Example: Lung cells have cilia to move dust away from lungs towards mouth.
Function of flagella?
Locomotion
Only flagellated cell in humans is sperm cell.
Function of microfilaments?
Help with muscle contraction and cell division
Function of intermediate filaments?
- Maintains cell structure and shape
- Resists tension
Function of nucleus?
- Control center
- Contains genetic material
Function of nuclear pores?
Allow proteins, RNA, and solutes to pass between nucleus and cytoplasm
Where is RNA produced?
In the nucleolus
Chromatin is composed of:
DNA and proteins
What are the four DNA bases?
- Adenine
- Thymine
- Cytosine
- Guanine
Adenine binds with thymine; cytosine binds with guanine.
Define:
Transcription
RNA assembled by RNA polymerase from one DNA strand
Define:
Initiation (transcription)
Promoter attaches to base, triggering transcription
Define:
Elongation (transcription)
- RNA polymerase unwinds DNA segment
- builds mRNA by aligning correct complimentary bases
Define:
Termination (transcription)
- When termination sequence reached, RNA is separated from gene.
- End of transcription
Define:
Translation
Process of creating polypeptide from mRNA strand
Initiation (translation)
- Ribosome binds to mRNA
Elongation (transcription)
- Binding of correct anticodons from tRNA to codons on mRNA
Termination (translation)
- Final codon on mRNA reached, stopping translation
- Protein is released
