Cells

What are the 3 main steps of cellular respiration and their locations

Glycolysis - cytoplasm

Krebs cycle - mitochondrial matrix

Oxidative phosphorylation - inner mitochondiral membrane

What are the main inputs and outputs of glycolysis

Glucose is broken down to 2x pyruvate molecules, and also produces 2 net ATP molecules, also an NADH+ is deprotonated to NAD

What are the main steps, inputs and outputs of the Krebs cycle

1. Starts with Acetyl-CoA adding its two carbons to oxaloacetate to form a 6C molecule

2. 6C molecules gets oxidised to reduce 2x NAD+ molecules to 2x NADH and 2x CO2 to turn it into a 4C

3. 4C phosphorylates ADP to ATP

4. 4C gets oxidised to reduce an FAD and an NAD+ molecule to FADH2 and NADH, forming oxaloacetate

IN: Acteyl CoA, oxaloacetate, 3x NAD+, FAD, ADP

OUT: Oxaloacetate, 3x NADH, FADH2, 2x CO2, ATP

What is the main reacting group of acetyl-CoA

Reactive thiol groupKet

Key stages in stem cell → specialised cell cycle

Maintenance

• Self renewal

• Commitment

Expansion

• Cell division + differentiation

Specialisation

• Further cell division + differentiation

3 main morphological characteristics to consider when classifying epithelia

Number of cell layers - Simple/stratified/pseudostratified (looks like stratified, but is actually only one cell thick)

Shape of cells - Squamous/cuboidal/columnar (in stratified, shape is based on topmost layer)

Special features - Cilia, keratin, microvilli, etc.

Major functions of epithelia tissue

1. Absorption

2. Secretion

3. Protection

4. Sensory perception

What is laminin

A molecule containing a cell binding and collagen binding region. Helps epithelial cells stick to collagen in basement membrane

What is the extra cellular matrix?

A mandatory part of any multicellular organism, keep cells together as well as many other functions.

the interstitial matrix between basement membrane and other cells is filled with fibrous protein (e.g. collaged) and polysaccharide gels

What holds the basal layer of the epidermis in place

Basal lamina (basement membrane)

What part of the epidermis regularly sheds

Stratum corneum

What part of the epidermis prevents water loss, and microbial invasion, and how

Stratum corneum are flat, anucelar keratinocytes embedded in a lipid matrix. These cells help prevent permeability of the skin

What are the 3 ways drugs can pass through the stratum corneum

1. Via sweat pores

2. Directly through the cells

3. Via hair follicles

3 components of cytoskeleton

• Intermediate filaments

• Microfilaments

• Microtubules

3 functions of cytoskeleton

• Maintaining tissue integrity (i.e. resisting stresses)

• Cell migration (microfilaments)

• Cell division (microtubules)

4 types of cell signalling

Local

Contact-dependent signalling

Paracrine signalling

• a signalling cell sends out signalling molecules to local nearby cells usually in the same tissue (basically close-range hormones)

Remote

Endocrine signalling

Synaptic signalling

4 Steps of cAMP/PKA cell signalling pathway

1. Signalling molecule (e.g. adrenaline) binds to G-protein-coupled receptor

2. α subunit of G-protein detaches, and attaches to Adenylyl cyclase enzyme, activating it

3. Activated adenylyl cyclase catalyses conversion of ATP to cAMP

4. cAMP activates protein kinase A (PKA), which goes off and phosphorylates other proteins

What is the function of a CREB protein?

CREB proteins (CRE-Binding protein) binds to CRE, which causes regulation of gene expression