Cellular Membrane Lipids Quiz

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What is the precursor of steroid hormones, vitamin D, and bile acids?

Flippases

Phospholipids

Cholesterol (correct)

Sphingolipids

Which lipid is the simplest phospholipid?

Sphingolipid

Cholesterol

Flippase

Phospholipid (correct)

What are the structural features shared by phospholipids, sphingolipids, and cholesterol?

Amphipathic nature

Steroid structure

Hydrophilic heads and hydrophobic tails (correct)

Carbon rings

Which lipid is formed by the combination of two phospholipids?

Cholesterol Signup and view all the answers

What are the functions of flippases in cells?

Aiding in lipid transport between membrane leaflets Signup and view all the answers

Which biochemical property is associated with lipid rafts in cellular membranes?

Rich in sphingolipids and cholesterol Signup and view all the answers

What is the rate limiting step in bile acid synthesis?

Conversion of cholesterol to 7-alpha hydroxycholesterol Signup and view all the answers

When intracellular cholesterol levels are low, is HMG CoA reductase phosphorylated or unphosphorylated?

Phosphorylated Signup and view all the answers

Where is SCAP-SREBP located when cholesterol levels are low?

In the endoplasmic reticulum Signup and view all the answers

What is the mechanism of action of statins?

Inhibition of cholesterol synthesis by targeting HMG CoA reductase Signup and view all the answers

Which organ STORES bile acids and bile salts?

Liver Signup and view all the answers

What is the common feature among all cellular membrane lipids?

Exposed polar head group Signup and view all the answers

Which lipid class is primarily synthesized in the Golgi apparatus?

Sphingolipids Signup and view all the answers

What is the function of lipid flippases in cellular membranes?

Move lipids to the inner leaflet Signup and view all the answers

Which lipid is the only phospholipid that is antigenic, meaning it is immunogenic?

Cardiolipin Signup and view all the answers

In apoptosis, what is one of the hallmarks observed on the outer face of the plasma membrane?

Exposure of phosphatidylcholine Signup and view all the answers

What is the primary difference between apoptosis and necrosis?

Energy dependence Signup and view all the answers

'Ceramide' in sphingolipids consists of which two components attached by an amide linkage?

'Sphingosine and fatty acid' Signup and view all the answers

'Phosphatidylethanolamine' belongs to which class of lipids?

'Phospholipids' Signup and view all the answers

'Mitomycin C' is known for inducing which process in cells?

'Apoptosis' Signup and view all the answers

What is the function of 'Scramblase' in cellular membranes?

Move lipids bi-directionally Signup and view all the answers

What is the function of phosphatidylserine exposure during apoptosis?

Recognition and uptake of apoptotic cells by phagocytes Signup and view all the answers

Which process moves phosphatidylserine from the cytoplasmic face to the extracellular face of the plasma membrane during apoptosis?

An ATP-dependent scramblase Signup and view all the answers

What is a characteristic feature of lipid rafts in cellular membranes?

Ordered regions distinct from disordered non-raft regions Signup and view all the answers

What is the role of lipid rafts in cellular functions?

Immune receptor signaling Signup and view all the answers

How does phosphatidylserine on apoptotic bodies help in clearance by phagocytes?

Triggering engulfment by phagocytes Signup and view all the answers

What type of proteins specifically partition to lipid rafts?

Proteins with lipid anchors or modifications Signup and view all the answers

Which organelle is primarily responsible for the synthesis of cholesterol?

Endoplasmic reticulum Signup and view all the answers

What is the primary function of HMG CoA reductase in cholesterol synthesis?

Regulate the rate-limiting step of cholesterol synthesis Signup and view all the answers

Which enzyme is responsible for the two-step cleavage of SREBP during cholesterol synthesis regulation?

Protease 2 Signup and view all the answers

What is the role of SCAP (SREBP Cleavage Activating Protein) in cholesterol synthesis regulation?

Senses intracellular cholesterol levels Signup and view all the answers

How do statins primarily affect cholesterol synthesis?

Competitively inhibit HMG CoA reductase Signup and view all the answers

What effect does glucagon have on HMGR expression and activity?

Inhibits HMGR expression and activity Signup and view all the answers

Which drug primarily acts at the small intestine brush border to inhibit cholesterol absorption?

Zetia (ezetimibe) Signup and view all the answers

What is a key advantage of using Zetia (ezetimibe) in reducing cholesterol levels?

Does not have significant side effects Signup and view all the answers