Biology Exam 2 Flashcards

Questions and Answers

What is cholesterol specifically classified as?

a steroid

Which hormones are made from cholesterol?

estradiol and testosterone

Which of the following characteristics is true for saturated fats?

They are solid at room temperature. (correct)

They have single bonds within the carbon chain. (correct)

They are liquid at room temperature.

They have double bonds within the carbon chain.

Which fat has the least number of hydrogen atoms?

unsaturated fat Signup and view all the answers

Of what are phospholipids important components?

the plasma membrane of animal cells Signup and view all the answers

What is the basic structure of a steroid?

four fused hydrocarbon rings Signup and view all the answers

Besides its use in hormone production, for what does the body use cholesterol?

production of bile salts Signup and view all the answers

What are the four classes of lipids and what is an example of each?

fats like margarine, waxes like the coating on feathers, phospholipids like cell membrane constituents, steroids like cholesterol Signup and view all the answers

Why have trans fats been banned from some restaurants?

Trans fat is produced by the hydrogenation of oil that makes it more saturated and isomerized. It increases LDL amounts. Signup and view all the answers

What is it about the structure of triglycerides that gives them their physical characteristics?

Unsaturated fats and trans fats have some double bonded carbon atoms, while saturated fats do not. Signup and view all the answers

Water moves via osmosis across plasma cell membranes in which direction?

from an area with a high concentration of water to one of lower concentration Signup and view all the answers

What happens to the membrane of a vesicle after exocytosis?

It fuses with and becomes part of the plasma membrane. Signup and view all the answers

If a doctor injected a patient with what was labeled as an isotonic saline solution, but then the patient died, and an autopsy revealed that several of the patient's red blood cells had burst, would it be true that the injected solution was really isotonic?

False Signup and view all the answers

____ is an essential fatty acid because it is not synthesized by the body.

Omega 3 Signup and view all the answers

___ can exist in cis and trans configuration.

Unsaturated fatty acids Signup and view all the answers

___ have kinks and are major constituents of liquid oils.

cis fatty acids Signup and view all the answers

___ can be hydrogenated to form saturated fatty acids.

saturated fats Signup and view all the answers

_ is bad cholesterol and _ is good cholesterol.

LDL; HDL Signup and view all the answers

Match the following lipid types with their descriptions:

Waxes = A class of lipids made of long-chain alcohols esterified to long-chain fatty acids Triglycerides = Fatty acids esterified with glycerol backbone Phospholipids = Triglycerides where one fatty acid chain is replaced by phosphate group Signup and view all the answers

___ is still a passive transport.

Facilitated diffusion Signup and view all the answers

___ needs ATP.

Active transport Signup and view all the answers

_ have fatty acids are esterified with glycerol backbone, and _ are triglycerides where one fatty acid chain is replaced by phosphate group.

Triglycerides; phospholipids Signup and view all the answers

What are the building blocks of nucleic acids?

nucleotides Signup and view all the answers

What may a nucleotide of DNA contain?

deoxyribose, thymine, and a phosphate group Signup and view all the answers

What is found in RNA that is not in DNA?

ribose and uracil Signup and view all the answers

Where is the largest amount of DNA found in a eukaryotic cell?

in the nucleus Signup and view all the answers

% of A = % & % of G = %

___T & ___C Signup and view all the answers

Meselson and Stahl's experiments proved that DNA replicates by which mode?

semi-conservative Signup and view all the answers

The experiments by Hershey and Chase helped confirm that DNA was the hereditary material on the basis of the finding of what?

Radioactive phosphorus was found in the cell. Signup and view all the answers

What are some differences between DNA and RNA?

DNA contains deoxyribose and thymine, while RNA contains ribose and uracil. Signup and view all the answers

Which molecule carries information in a form that is inherited from one generation to another?

Hereditary information is stored in DNA. Signup and view all the answers

What do RNA and DNA have in common?

Both contain four different nucleotides. Signup and view all the answers

Study Notes

Cholesterol and Lipids

Cholesterol is classified as a steroid.
Hormones synthesized from cholesterol include estradiol and testosterone.
Saturated fats are solid at room temperature and have single bonds in their carbon chains.
Unsaturated fats have fewer hydrogen atoms compared to saturated fats.
Phospholipids are key components of the plasma membrane in animal cells.
A steroid's structure consists of four fused hydrocarbon rings.
Cholesterol also aids in the production of bile salts.
Four classes of lipids include:
- Fats (e.g., margarine)
- Waxes (e.g., feathers' coating)
- Phospholipids (e.g., cell membrane constituents)
- Steroids (e.g., cholesterol).
Trans fats are banned in some restaurants due to their harmful effects on health; they are produced by hydrogenating oils which increases saturation and LDL levels.
The structure of fatty acids influences their physical properties; unsaturated and trans fats contain double bonds, while saturated fats do not.

Transport Mechanisms

Water moves via osmosis from areas of high water concentration to low concentration across plasma membranes.
The membrane of a vesicle fuses with the plasma membrane after exocytosis.
An injection labeled as isotonic that causes red blood cell rupture indicates it was hypotonic instead.
Facilitated diffusion is a form of passive transport, while active transport requires ATP.

Fatty Acid Configurations

Omega-3 is an essential fatty acid that the body cannot synthesize.
Unsaturated fatty acids can exist in both cis and trans configurations.
Cis fatty acids have kinks in their structure and are major components of liquid oils.
Saturated fats can be hydrogenated to become saturated fatty acids.

Cholesterol Types

LDL (low-density lipoprotein) is referred to as 'bad' cholesterol, while HDL (high-density lipoprotein) is known as 'good' cholesterol.

Nucleic Acids

Waxes are long-chain alcohols esterified to fatty acids, while triglycerides consist of fatty acids esterified with a glycerol backbone.
The building blocks of nucleic acids are nucleotides.
A DNA nucleotide may consist of deoxyribose, thymine, and a phosphate group.
RNA contains ribose and uracil, which are absent in DNA.
The nucleus holds the largest amount of DNA within a eukaryotic cell.
The percentage of adenine (A) equals thymine (T), and guanine (G) equals cytosine (C).
Meselson and Stahl's experiments showed that DNA replication is semi-conservative.
Hershey and Chase's experiments demonstrated that DNA is the hereditary material through the detection of radioactive phosphorus in cells.
DNA differs from RNA; DNA has deoxyribose and thymine, while RNA has ribose and uracil.
Hereditary information is stored in DNA, and both RNA and DNA share the characteristic of containing four different nucleotides.

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Prepare for your biology exam with these flashcards focused on cholesterol, hormones, and fat characteristics. Test your knowledge on the classification of steroids and the properties of saturated fats. Perfect for quick revision and mastering key concepts in biology.