The Cellular/Tissue Level of Organization Flashcards
1
Q
What are the functions of centrosomes and centrioles?
A
- Non-membranous organelles
- Movement of chromosomes during cell division
- Organization of microtubules in cytoskeleton
2
Q
What is the cytoskeleton?
A
- the structural framework
- gives cytoplasm strength and flexiblity
- Proteins organized in microfilaments (fine filaments) and microtubules (slender tubes)
- movement of cellular structures and materials
3
Q
What is the plasma membrane?
A
- Phospholipid bilayer
- Contains
- hydrophilic heads, hydrophobic fatty acid tail
- lipids, proteins, carbohydrates, steroids, cholesterol
- Functions
- Physical isolation
- Controls entry/exit of materials
- Sensitivity to environment
- Structural support
4
Q
Cytoplasm vs Cytosol
A
- Cytoplasm: all materials inside and outside the nucleus
- Cytosol: intracellular fluid contained in the cytoplasm
5
Q
The six membrane proteins in the plasma membrane
A
- anchoring: attach to in/outside structures and stabilize its position
- recognition: identify cells as normal/abnormal
- receptor: bind and respond to ligands
- carrier: bind and transport solutes using ATP
- channel: transports water and small solutes
- enzymes: catalyze reactions
6
Q
What are cilia?
A
- Long extensions of the plasma membrane (contains microtubules)
- Primary (non-motile) cilium: sensor, signaling
- Motile cilium: move materials over cell surfaces
7
Q
What are microvilli?
A
- Extensions of plasma membrane (contains microfilaments)
- Increases SA for absorption of extracellular materials
8
Q
Contents of the nucleus
A
- nuclear envelope: double membrane
- nuclear pores: communication passages
- DNA: instructions for protein synthesis
- nucleoplasm: fluid containing nuclear matrix with fine filaments for structural support
- nucleolus: made of RNA, enzymes, histones to synthesize rRNA and proteins
- nucleosomes: DNA coiled around histones
9
Q
What is the Golgi apparatus?
A
- like a post office
- storage, alteration, packaging of secretory products
- cisternae: 5/6 flattened membranous discs
- Produces lysosomes
- digestive enzymes
- intracellular removal of damaged organelles or pathogens
10
Q
What is the endoplasmic reticulum?
A
- synthesize proteins/carbs/lipids
- store synthesized molecules or materials absorbed
- transport materials
- smooth ER: detoxification
- rough ER (covered in ribosomes): protein synthesis
11
Q
What is transcription?
A
- Copies instructions from DNA to mRNA in the nucleus
- Via RNA polymerase
- Binds to promoter region on template strand
- introns removed, exons spliced together
- Cap: Modified guanine nucleotide
- Tail: Extra adenine nucleotides
- mRNA leaves nucleus to cytoplasm via nuclear pores
12
Q
What is translation?
A
- ribosomes on rough ER reads code from mRNA in the cytoplasm
- assembles amino acids into polypeptide chain via tRNA
13
Q
How do somatic cells divide?
A
- DNA replication: Duplicates genetic material exactly
- Mitosis: Divides genetic material exactly
- Cytokinesis: Divides cytoplasm and organelles into two daughter cells
14
Q
What is meiosis?
A
- Two cell-division steps producing gametes (ova and sperm)
- Only occurs in gonads (ovaries and testes)
15
Q
Describe the characteristics of epithelial tissue
A
- Cellularity: cell junctions
- Polarity: apical and basal surfaces
- Attachment: basement membrane
- Avascularity (no blood vessels)
- Innervated (supplied with nerves)
- Regeneration
