Nutrition: Fats and Essential Fatty Acids

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Questions and Answers

What process is used to create trans fats?

Partial hydrogenation of oils (correct)

Deep frying vegetable oils

Sefiltration of unsaturated fats

Complete hydrogenation of oils

How do trans fats affect cholesterol levels in the body?

They have no effect on cholesterol levels.

They increase LDL and decrease HDL. (correct)

They decrease both HDL and LDL.

They increase HDL and decrease LDL.

Which fatty acids must be obtained through diet?

Palm and coconut fatty acids

Monounsaturated fatty acids

Essential fatty acids (correct)

Saturated fatty acids

What is the primary function of cholesterol in the body?

To maintain cell membrane flexibility Signup and view all the answers

Which of the following describes omega-3 fatty acids?

They have the first double bond at the third carbon. Signup and view all the answers

What effect did public health research in the 1990s have on trans fats?

Trans fats were shown to have adverse health effects. Signup and view all the answers

Which statement about omega-9 fatty acids is correct?

They can be synthesized by the body but not efficiently. Signup and view all the answers

What effect does partial hydrogenation have on vegetable oils?

Increases their stability Signup and view all the answers

What is the primary role of HDL and LDL in the bloodstream?

Transport fats Signup and view all the answers

What structure do phospholipids form in cell membranes?

Phospholipid bilayer Signup and view all the answers

What characteristic of phospholipids makes them suitable for cell membranes?

Amphipathic nature Signup and view all the answers

How do multicellular organisms generally increase their size?

By increasing cell number Signup and view all the answers

Which of the following is a characteristic of microvilli?

They aid in nutrient diffusion Signup and view all the answers

What is the typical diameter range of most human cells?

5 to 20 µm Signup and view all the answers

What limitation constrains the size of cells in multicellular organisms?

Diffusion of nutrients and waste Signup and view all the answers

What component is considered a primary part of cell membranes along with phospholipids?

Cholesterol Signup and view all the answers

What is the approximate height range of the cells described?

2-5 micrometers Signup and view all the answers

Which statement is NOT part of the cell theory?

Cells can spontaneously generate under certain conditions. Signup and view all the answers

What provides the fluidity of the plasma membrane?

Cholesterol and unsaturated fats Signup and view all the answers

What is the main function of the plasma membrane?

To control the permeability of the cell Signup and view all the answers

What characteristic of phospholipids affects the plasma membrane's structure?

They consist of a polar head and two nonpolar tails. Signup and view all the answers

What is cytosol?

The fluid component of the cytoplasm Signup and view all the answers

What do nucleoli inside the nucleus indicate?

Ribosome production is taking place Signup and view all the answers

What are the two main types of cells defined in the content?

Eukaryotic and prokaryotic Signup and view all the answers

Which of the following accurately describes the composition of the plasma membrane?

It consists of a phospholipid bilayer. Signup and view all the answers

What role do receptor proteins play in the plasma membrane?

They bind to external substances affecting cell function. Signup and view all the answers

What is one main feature that distinguishes prokaryotic cells from eukaryotic cells?

Prokaryotic cells do not have a nucleus. Signup and view all the answers

Which type of membrane protein allows specific substances to cross the membrane?

Transporters Signup and view all the answers

What constitutes the nucleoid region in prokaryotic cells?

A single, circular DNA molecule. Signup and view all the answers

In which of the following organisms would you find eukaryotic cells?

Fungi Signup and view all the answers

Which component of the plasma membrane helps maintain its fluidity?

Cholesterol Signup and view all the answers

What is the primary function of gap junctions in cellular structures?

To allow direct communication between adjacent cells. Signup and view all the answers

What is the primary component that distinguishes Gram-positive bacteria from Gram-negative bacteria?

An outer membrane with lipopolysaccharide Signup and view all the answers

Which of the following structures aids in locomotion for prokaryotic cells?

Flagellum Signup and view all the answers

What is the role of the capsule in prokaryotic cells?

Protection Signup and view all the answers

Which of the following statements about eukaryotic cells is correct?

They have larger and more complex structures than prokaryotes. Signup and view all the answers

What crucial function does the nucleus serve in eukaryotic cells?

Containing DNA Signup and view all the answers

Which of the following is a characteristic of the cytoplasm in eukaryotic cells?

Is a semi-fluid mixture containing organelles and cytoskeleton Signup and view all the answers

What distinguishes the double membrane of the nuclear envelope?

Contains two lipid bilayers Signup and view all the answers

Which of the following structures is responsible for attaching prokaryotic cells to substrates?

Pilus Signup and view all the answers

Study Notes

Trans Fats

Trans fats are unsaturated fatty acids where the hydrogens are on opposite sides of the double bond.
Trans fats are more stable than cis fats.
Trans fats are made by partial hydrogenation of vegetable oils.
Trans fats increase LDL ("bad") cholesterol and decrease HDL ("good") cholesterol.
Adding partially hydrogenated oils to food products was banned by Health Canada in September 2018.
Some trans fats occur naturally in meat and milk products from ruminants.

Essential Fatty Acids

Essential fatty acids must be obtained from our diet.
Essential fatty acids are polyunsaturated.
Omega-3 and omega-6 fatty acids are essential.
Omega-3 fatty acids have the first double bond on the 3rd carbon from the end opposite the carboxyl group.
Omega-6 fatty acids have the first double bond on the 6th carbon from the end opposite the carboxyl group.
Omega-9 fatty acids can be synthesized by the body, but some consider them essential.

Cholesterol

Cholesterol is found in animal cell membranes.
Most cholesterol in the body is synthesized by the liver.
Liver and brain cells have the highest concentration of cholesterol.
Functions of cholesterol:
- Maintain cell membrane flexibility.
- Production of steroid hormones.
- Production of bile for fat breakdown.
- Transport fats through the bloodstream as HDLs and LDLs.

Phospholipids

Phospholipids are the primary component of cell membranes, along with cholesterol and proteins.
They have two non-polar fatty acid chains (tails) and a polar "head" containing a phosphate group.
The fatty acids are often unsaturated.
They are amphipathic, meaning they have both polar and non-polar groups.

Cell Membranes

Cell membranes are composed of phospholipids, cholesterol, and proteins.
The membrane is made of two layers of phospholipids, with the non-polar "tails" pointing toward each other.
This is called the phospholipid bilayer.

Cell Theory

All living things are composed of cells
The cell is the basic unit of life and the smallest independent unit that can survive.
All cells come from pre-existing cells.
All cells contain DNA, which is passed on during cell division.
All cells are either prokaryotic or eukaryotic.

Plasma Membrane

The plasma membrane forms the cell boundary.
Controls the permeability of the cell to water and dissolved substances.
Most hydrophilic molecules require channels or transporters to pass through the hydrophobic core of the membrane.
Cytoplasm is all the contents inside the cell, including organelles.
Cytosol is the fluid component of the cytoplasm.

Fluid Mosaic Model

The plasma membrane is described by the fluid mosaic model.
It contains a mosaic of phospholipids with proteins and cholesterol.
The phospholipids have mostly unsaturated fats, giving the membrane fluidity.
Proteins and cholesterol can move within the membrane.

Membrane Proteins

Receptors bind to substances outside the cell and influence cell function.
Self antigens act as markers on the membrane, such as blood-type proteins and MHC.
Enzymes catalyze chemical reactions within the cell.
Transporters move substances across the membrane, such as ion channels or carrier proteins.
Adhesion proteins connect cells together.
Gap junctions allow direct communication between cells.

Prokaryotic Cells

Lack a nucleus and complex internal membrane systems (organelles).
Two main types: Eubacteria and Archaebacteria.
Contain a nucleoid region with a single, circular DNA molecule, but no membrane.
Cytoplasm contains ribosomes for protein synthesis.
Cell membrane composed of phospholipids, cholesterol, and proteins.
Cell wall has two general types:
- Gram-positive: composed of peptidoglycan.
- Gram-negative: composed of peptidoglycan and an outer membrane with lipopolysaccharide (LPS).
Capsule is an optional extra layer of protection made of protein.
Flagella are whip-like protein fibers for locomotion and feeding.
Pili are short, hair-like structures for attachment and genetic exchange.

Eukaryotic Cells

Have a nucleus and complex internal membrane-bound organelles.
Include protists, fungi, plants, and animals.
Larger and more complex than prokaryotic cells.
Encased by a plasma membrane.
Contain cytoplasm with cytosol, organelles, and a cytoskeleton.
Nucleus is a membrane-bound organelle that contains DNA.
Some eukaryotic cells have a cell wall, but not animal cells.

Nucleus

Contains DNA organized into chromosomes.
In humans, there are 46 chromosomes (called chromatin here).
Nuclear envelope is a double membrane (two lipid bilayers).
Nucleolus is a dense region within the nucleus where ribosome subunits are assembled.

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Description

This quiz explores the crucial topics of trans fats, essential fatty acids, and cholesterol. You'll test your knowledge on their characteristics, dietary importance, and health implications. Perfect for anyone studying nutrition or health sciences.