BIO 1140 Lecture Notes - Lecture 4: Glycerol, Inositol, Phosphatidylserine

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indigomoose336

4 Feb 2017

School

University of Ottawa

Department

Biology

Course

BIO 1140

Professor

Caroline Petit- Turcotte

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Document Summary

Discuss the role of membranes, and in particular the plasma membrane, in a. Cell: they act as a boundary with selective permeability. The membrane structure (phospholipid bilayer) contributes to this. It is dynamic and uid but has other components that can control what passes through. Some things can easily pass through passive diffusion, going down their concentration gradient. Some require helper proteins to transfer them against their concentration gradient. The polarity of the heads and tails also determine what types of molecules and solutes can pass thorugh: they organize and scaffold > form internal compartments (er, nuclear) and an internal network of membranes. Properties in the discussion: phospholipids naturally form a bilayer due to their hydrophobic and hydrophilic parts, and are able to move laterally in any direction they wish. Trans-double bonds in their hydrocarbon tails gives the membrane more empty space for them to move around and be more fluid.

Related Questions

1 Which of the following statements is false?

(a) CO₂ and O₂ can diffuse freely across the cell membranes.

(b) The differences in permeability between artificial lipid bilayers and cell membranes arise from variations in phospholipid content.

(d) Cells expend energy in the form of ATP hydrolysis to maintain ion concentrations that differ from those found outside the cell.

2 Cells use membranes to help maintain set ranges of ion concentrations inside and outside the cell. Which of the following ions is the most abundant inside a typical mammalian cell?

(a) Na⁺

(b) K⁺

(d) Cl^â

3 Pumps are transporters that are able to harness energy provided by other components in the cells and drive the movement of solutes across membranes, against their concentration gradient. This type of transport is called _____________.

(a) active transport.

(b) free diffusion.

(d) passive transport.

harlequinbuffalo618

1) This is a thermodynamics questions

In your body, normal osmolarity of blood serum is just under 0.3 molar. Because cell membranes are permeable to water, the osmolarity of intracellular fluid is approximately equal to that of extracellular fluid (though the intracellular and extracellular composition in terms of specific ions and proteins is quite different). As an aside, measurement of osmolarity of serum is an important clinical test used to check for dehydration or other imbalances of water and electrolytes.

a) In the supplemental information, the osmosis example presented involves sucrose as a solute, but the van't Hoff equation also applies for other solutes. Using this formula (â = cRT, where â is the excess pressure), calculate the osmotic pressure associated with 0.3 molar concentration of osmolytic particles (e.g., ions, proteins, or other dissolved particles) in contact with pure water through a semi-permeable membrane at physiological temperature of 310 K. Express your results in atmospheres of pressure (1 atmosphere of pressure is 1.0x10⁵ Pascal, where 1 Pascal is a Newton/m²).

b) A biological cell membrane is a bilayer of phospholipid molecules, only a few nanometers thick, and can basically be thought of much like a soap bubble, except immersed in aqueous solution. If cells are placed in pure water, they often swell and burst in just a few minutes. Explain why this would happen.

grayporcupine495

1) Which of the following is a component of a vertebrate kidney? (Select all correct choices.)

		glomerulus
		Bowman's capsule
		renal tubules
		collecting ducts
		Malphigian tubules

In organisms, the ability to control osmosis depends on the properties of the plasma membranes of individual cells. Based on their ability to permit the free movement of water and some solutes, these membranes are best described as: (select all correct choices)

		impermeable.
		permeable.
		semipermeable.
		diffusible.
		impervious.

3)I selected cortex; inner medulla, it was wrong.

The loops of Henle create a concentration gradient in the interstitial fluid surrounding the loop, with the concentration highest in the ____________ and lowest in the ____________ of the kidney.

		inner medulla; cortex
		outer medulla; inner medulla
		outer medulla; cortex
		cortex; inner medulla
		cortex; outer medulla

The main solutes in the filtrate as it enters the distal convoluted tubule are: (select all correct choices)

		urea.
		electrolytes.
		other wastes.
		amino acids.
		nucleotides.

5) Ensure all correct choices are selected, for this question I only selected osmosis and it was wrong,

Water moves by: (select all correct choices)

		random molecular motion.
		active transport.
		passive transport.
		osmosis.
		facilitated diffusion

Compared to sexual reproduction, asexual reproduction: (select all correct choices)

	requires less investment in attracting mates.
	allows much more rapid population growth.
	is rarely found as the sole mechanism of reproduction.
	results in the production of genetically identical cells or individuals.
	involves meiosis and fertilization as core processes.

A key difference between hormonal regulation of the reproductive systems of males and females is that:

	LH and FSH are released only in females.
	LH and FSH are released only in males.
	LH and FSH are released cyclically in females but nearly continuously in males.
	LH is released in males and FSH is released in females.
	LH is released continuously in males and FSH is released cyclically in females.

True or false: In response to LH and FSH, ovaries secrete estrogen and progesterone.

	true
	false

During the luteal phase of the menstrual cycle, if the oocyte is not fertilized, a number of events occur which are listed below. Select the answer that places the events in the correct chronological order.

Events:
1. the lining of the uterus is shed
2. the corpus luteum secretes progesterone
3. follicle cells are converted to the corpus luteum
4. the corpus luteum degenerates
5. estrogen and progesterone levels fall

	3, 2, 4, 5, 1
	1, 2, 3, 4, 5
	2, 4, 3, 1, 5
	4, 3, 2, 1, 5
	5, 2, 3, 4, 1

10)

If an antibody is missing its Fc fragment, what would happen if this antibody encounters its target antigen in the bloodstream? Select all correct choices.

	The antibody would be able to bind the antigen at a specific epitope.
	The antibody would be able to bind the antigen, but not at an epitope site.
	The antibody would not be able to bind to the antigen.
	The antibody would be able to activate components of the complement system.
	The antibody would not be able to activate components of the complement system.

11)

If an individual carries a mutation that results in a complete lack of MHC class I proteins, how would the individualâs immune response be affected? Select all correct choices.

	Memory cell antibodies would not be able to attach to antigen epitopes.
	Cytotoxic T cells would not be able to target (and destroy) infected cells.
	Helper T cells would not be able to interact with antigen-presenting cells.
	Plasma cell antibodies would not be able to attach to antigen epitopes.

12)

Which of the following statements is true regarding T cell receptors? Select all correct choices.

	They recognize antigen-MHC complexes.
	They contain variable and constant regions.
	They are composed of two heavy (H) chains and two light (L) chains.
	They are formed by the rearrangement of V, J, C, and D gene segments.
	They can be found in the bloodstream independent of T cells.

sapphireworm318

BIO 1140 Lecture Notes - Lecture 4: Glycerol, Inositol, Phosphatidylserine

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