PRE-NURSING ENTRANCE EXAM (TEAS EXAM)

Thursday, February 19, 2015

TEST YOUR KNOWLEDGE ON CELL STRUCTURE AND FUNCTION

You can review the cell structure and functions from the past lessons and then proceed to the multiple choice questions to test your skills.

Here is a link to practice on questions related to the cell structure and functions.

OVERVIEW AND MULTIPLE CHOICE QUESTIONS ON CELL RESPIRATION

We have already discussed cell respiration but here is a recap. Cellular respiration is the process by which the chemical energy trapped in food molecules is released and partially captured in the form of ATP. All the different classes of food substances, carbohydrates, fats, and proteins can all be used as fuels in cellular respiration. They have to be converted to glucose before they can be used in the chemical pathway. The three stages of cellular respiration are:

1. Glycolysis: This occurs in the cytosol. In glycolysis, the 6-carbon sugar, glucose, is broken down into two molecules of a 3-carbon molecule called pyruvate. This change is accompanied by a net gain of 2 ATP molecules and 2 NADH molecules.

2. The Krebs cycle: This occurs in the matrix of the mitochondria. This takes place in the presence of oxygen.It generates a pool of chemical energy which includes ATP, NADH, and FADH_2, from the oxidation of pyruvate, the end product of glycolysis.

3. Oxidative phosphorylation: This occurs in the electron transport chain. The electron transport chain is located on the inner mitochondrial membrane and consists of a series of molecules, mostly proteins. The electron transport chain allows the release of large amount of chemical energy stored in reduced NAD⁺ (NADH) and reduced FAD (FADH₂). This energy is captured in the form of ATP (3 ATP per NADH and 2 ATP per FADH₂).

In the absence of oxygen, fermentation occurs. Fermentation leads to lactic acid production.

Each molecule of glucose can generate 36-38 molecules of ATP in aerobic respiration.
Only 2 ATP molecules are generated in respiration without oxygen (through glycolysis and fermentation).

Click on this link to try the quiz.

Wednesday, February 18, 2015

MAKING INFERENCES AND CONCLUSIONS FROM SCIENTIFIC EXPERIMENTS

You will be tested on your understanding of scientific experiments and your ability to make inferences and conclusions from various data, graphs, and scenarios. The science passages below can help you practice on some of these questions.

1. Reading Comprehension 1
2. Reading Comprehension 2
3. Reading Comprehension 3
4. Reading Comprehension 4
5. Reading Comprehension 5
6. Reading Comprehension 6
7. Reading Comprehension 7

Monday, February 16, 2015

WHAT ARE CATECHOLAMINES?

The nervous system consists of the central and the peripheral nervous systems. The central nervous system consist of the brain and spinal cord while the peripheral nervous system is made up of the sympathetic and parasympathetic nervous systems. The sympathetic nervous system is responsible for fight-and-flight responses whilst the parasympathetic is responsible for calming you down.

Within the sympathetic nervous system, there are two neurotransmitters:

Noradrenaline (also referred to as norepinephrine)
adrenaline (also referred to as epinephrine)

These are known as catecholamines.

Noradrenaline is the main neurotransmitter of the sympathetic nerves in the cardiovascular system. It plays a major role in tonic and reflexive changes in cardiovascular tone. The sympathetic noradrenergic system is active even when the individual is at rest.
Adrenaline is the main hormone secreted by the adrenal medulla. Adrenaline is a major determinant of responses to metabolic challenges to homeostasis.

What are some of the fight-and-flight responses?