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
16
Q
Describe the functions of epithelial tissue
A
- Physical protection
- Control permeability
- Sensation
- Specialized secretions (glandular epithelium)
17
Q
Describe the classification of epithellial tissue
A
- Based on layers
- Simple: single layer
- Stratified: several layers
- Based on shape
- Squamous: thin and flat
- Cuboidal: square
- Columnar: tall, slender rectangles
-
Glandular epithelia
- Secrete signaling molecules, e.g. hormones
- Exocrine: secrete thru ducts onto epithelial surfaces
- Endocrine: relase directly into the blood
18
Q
Describe the functions of connective tissue
A
- Connects body parts (structural framework)
- Transports fluids/dissolved materials
- Protects organs
- Supports tissue
- Stores energy reserves
19
Q
Describe the characteristics of connective tissue
A
- Main components
- Ground substance: fluid that fills intercellular space
- Fibres: collagen (strength), elastin (networks), reticular (strength and networks)
- Cells
20
Q
Describe the classification of connective tissue
A
-
Connective tissue proper
- Loose: more ground substance, less fibres
- Dense: less ground substance, more fibres
-
Supporting connective tissues
- Cartilage: gel-type ground substance for shock absorption and protection
- Bone: calcified (rigid due to calcium salts), for weight support
-
Fluid connective tissues
- Blood: carries formed elements
- Lymph
21
Q
Describe the three types of muscle tissue
A
-
Skeletal muscle tissue
- Cover the skeleton
- Responsible for movement
- Voluntary motion
- Multinucleated
- Striated, containing sarcomeres
-
Cardiac muscle tissue
- Found in the heart
- Contract to pump blood out of the heart
- Involuntary motion (autonomic nervous system)
- Striated, containing sarcomeres
-
Smooth muscle tissue
- Found in organs
- e.g. Blood vessel walls: regulate pressure, distribute blood
- Involuntary motion (autonomic nervous system)
- NOT striated
22
Q
Describe the two types of neural tissue
A
-
Neurons
- Nerve cells
- Perform electrical communication
-
Neuroglia
- Supporting cells
- Protect and supply nutrients to neurons
23
Q
Describe the cell parts of a neuron
A
-
Cell body
- Nucleus and nucleolus
-
Dendrites
- Surface area for receiving signals
-
Axon (nerve fibre)
- the conducting region
- carries electrical signals to their destination
24
Q
Define extracellular fluid
A
- watery medium that surrounds cells
- also known as interstitial fluid
25
Q
Differentiate between nonmembranous and membranous organelles
A
- Nonmembranous: not completely enclosed by membranes, components in direct contact with cytosol
- Membranous: isolated from cytosol by phospholipid membranes
26
Q
Describe the phases of interphase
A
- G0
- normal cell functions
- G1
- cell growth
- organelle duplication
- protein synthesis
- S
- DNA replication
- histone synthesis
- G2
- protein synthesis
27
Q
Describe mitosis
A
-
Prophase
- chromatin condenses
- chromosomes become visible
- centrioles migrate to opp poles
- spindle fibers develop
- nuclear membrane disintegrates.
-
Metaphase
- chromosomes attach to spindle fibers
- chromosomes line up along the metaphase plate
-
Anaphase
- chromatids of chromosomes separate
- chromatids migrate toward opp poles
-
Telophase
- nuclear membrane forms
- chromosomes disappear
