Which of the following types of membrane is associated with the skin?

This question tests your understanding of gene expression and protein synthesis inside the cell.

The key statement in the question is:

“The cell is able to make copies of its genetic information but is unable to produce encoded proteins.”

This tells us that:

• DNA replication is working
• But protein synthesis is not occurring

The cellular structure responsible for protein synthesis is the ribosome.

1. How Genetic Information Becomes Protein

Cells use a process called gene expression to convert genetic information into proteins.

This occurs in two major steps:

Step 1: Transcription

DNA → mRNA

• Occurs in the nucleus
• The DNA code is copied into messenger RNA (mRNA)

The question states the cell can make copies of its genetic information, meaning this step is working.

Step 2: Translation

mRNA → Protein

• Occurs at the ribosome
• Ribosomes read the mRNA instructions and build proteins from amino acids

If the cell cannot produce proteins, the issue is likely with the ribosomes, where translation occurs.

2. What Ribosomes Do

Ribosomes are the cellular structures responsible for protein synthesis.

Their function is to:

• Read mRNA instructions
• Assemble amino acids
• Build polypeptide chains (proteins)

Ribosomes can be found:

• Floating freely in the cytoplasm
• Attached to the rough endoplasmic reticulum (RER)

Without ribosomes, the cell cannot produce proteins, even if DNA and mRNA are present.

Why the Other Options Are Incorrect

Acrosome

The acrosome is a structure found in sperm cells that contains enzymes used to penetrate the egg during fertilization.

It has nothing to do with protein production in general cells.

Centrosome

The centrosome organizes microtubules and helps form the mitotic spindle during cell division.

It is involved in cell division, not protein synthesis.

Golgi Apparatus

The Golgi apparatus modifies, sorts, and packages proteins after they are made.

It does not produce proteins.

If ribosomes fail, proteins never reach the Golgi.

Key Takeaway Points

Ribosomes make proteins

Protein synthesis occurs during translation at ribosomes.

DNA → RNA → Protein

This process is called the central dogma of molecular biology.

If proteins cannot be produced, suspect ribosomes

Even if DNA replication and transcription work normally, protein synthesis cannot occur without ribosomes.

Ribosomes are found in two locations

• Free ribosomes → make proteins used inside the cell
• Rough ER ribosomes → make proteins for export or membranes

TEAS Exam Memory Trick

Think of ribosomes as protein factories.

If a question mentions:

• Protein production
• Translation
• mRNA being converted to protein

➡ The answer is usually ribosomes.

This question involves phase changes and gas pressure.

The key concept here is sublimation, which is when a substance changes directly from a solid to a gas without passing through the liquid phase.

Dry ice is the solid form of carbon dioxide (CO₂). When dry ice sublimates, it turns directly into CO₂ gas.

1. What Happens When Dry Ice Sublimates?

When dry ice changes from solid CO₂ to gaseous CO₂:

• Solid CO₂ molecules become free-moving gas molecules
• The gas molecules spread out and occupy more space
• The number of gas particles in the container increases

Because the container is sealed, the gas cannot escape.

2. Why Pressure Increases

Pressure in a gas occurs when gas molecules collide with the walls of a container.

As dry ice sublimates:

1. More CO₂ gas molecules are produced.
2. These gas molecules move freely throughout the container.
3. They collide with the container walls more frequently.

More collisions with the container walls result in greater pressure.

So the best explanation is that gas CO₂ particles occupy more space, leading to increased pressure.

3. Gas Behavior vs Solid Behavior

When CO₂ changes from solid → gas, the particles become much farther apart and mobile, which increases pressure inside a sealed container.

Why the Other Options Are Incorrect

Gas CO₂ molecules move faster when CO₂ is a solid.

Molecules in a solid move much less than gas molecules. Gas molecules move faster because they have greater freedom of movement.

CO₂ molecules combine to form larger molecules in the gas phase.

CO₂ molecules do not combine during sublimation. They remain individual CO₂ molecules.

CO₂ particles exert less force on the container walls as a gas.

Gas particles actually exert more force because they collide with the container walls frequently.

Key Takeaway Points

Sublimation

Sublimation is the change of state from:

Solid → Gas

Example: Dry ice (solid CO₂) → CO₂ gas

Gas pressure

Gas pressure is caused by collisions of gas particles with container walls.

More particles = more collisions = higher pressure

Gas particles spread out

Gas molecules move freely and occupy more space than solid particles.

Sealed containers trap gases

If gas forms inside a sealed container, the pressure will increase because the gas cannot escape.

TEAS Exam Memory Trick

Remember:

More gas particles → More collisions → Higher pressure

The pH scale is logarithmic, not linear. That is the key idea.

Each change of 1 pH unit represents a tenfold change in hydrogen ion concentration H+.

• A lower pH means more acidic
• A higher pH means more alkaline or more basic

So, comparing:

• pH 3
• pH 4

A substance with a pH of 3 has 10 times more hydrogen ions than a substance with a pH of 4, which makes it 10 times more acidic.

That is why B is correct.

Why the Other Choices Are Incorrect

A. A substance with a pH of 3 is two times more acidic than a substance with a pH of 4.
This is incorrect because the pH scale does not increase by simple doubling. A difference of 1 pH unit means a 10-fold change, not a 2-fold change.

C. A substance with a pH of 3 is two times more alkaline than a substance with a pH of 4.
This is incorrect because pH 3 is more acidic, not more alkaline. Also, the “two times” part is wrong.

D. A substance with a pH of 3 is 10 times more alkaline than a substance with a pH of 4.
This is incorrect because pH 3 is not more alkaline. It is more acidic.

Key Concept to Remember

The pH formula is based on the concentration of hydrogen ions:

• Lower pH = higher [H⁺] = more acidic
• Higher pH = lower [H⁺] = more basic/alkaline

Examples:

• pH 2 is 10 times more acidic than pH 3
• pH 3 is 10 times more acidic than pH 4
• pH 2 is 100 times more acidic than pH 4

That last example happens because:

• from 4 to 3 = 10 times
• from 3 to 2 = another 10 times
• total = 10 × 10 = 100 times

Take Away Points

• The pH scale is logarithmic.
• A difference of 1 pH unit = 10 times change in acidity/basicity.
• Lower pH values are more acidic.
• Higher pH values are more alkaline/basic.
• Do not treat pH differences as simple addition or doubling

This question is asking which cell structure is a system of interconnected tubes and is involved in protein production. The correct answer is the rough endoplasmic reticulum (rough ER).

1. What is the Rough Endoplasmic Reticulum?

The rough endoplasmic reticulum is a network of membranous sacs and interconnected tubes found inside eukaryotic cells. It is called “rough” because ribosomes are attached to its outer surface, giving it a bumpy appearance under a microscope.

Those ribosomes are the key reason the rough ER is involved in protein production.

2. How the Rough ER Helps Make Proteins

Protein production happens in stages:

Step 1: DNA instructions are transcribed into mRNA

This occurs in the nucleus.

Step 2: Ribosomes read the mRNA

Ribosomes attached to the rough ER translate the mRNA code into a chain of amino acids.

Step 3: The rough ER begins processing the protein

Once the protein is made, the rough ER helps:

• fold the protein correctly
• modify it
• transport it to other parts of the cell, often to the Golgi apparatus

So while ribosomes directly assemble proteins, the rough ER is the interconnected tube system associated with making and processing proteins.

3. Why “interconnected tubes” matters

The wording of the question points strongly to the endoplasmic reticulum, because the ER is literally a membrane network spread throughout the cytoplasm.

There are two types of ER:

• Rough ER → has ribosomes, involved in protein synthesis
• Smooth ER → no ribosomes, involved in lipid synthesis and detoxification

Since the question specifies protein production, it must be the rough endoplasmic reticulum.

Why the Other Options Are Incorrect

the cytoskeleton

The cytoskeleton is a framework of protein fibers that helps the cell maintain its shape, move, and transport materials internally.

It is not the organelle primarily responsible for protein production.

the lysosome

A lysosome contains digestive enzymes that break down waste materials, damaged organelles, and foreign substances.

Its role is digestion and recycling, not protein production.

basal bodies

Basal bodies help organize microtubules and are involved in forming cilia and flagella.

They are not involved in protein synthesis.

Key Takeaway Points

1️⃣ Rough ER is the protein-processing membrane network

If a question asks about:

• interconnected tubes
• ribosomes attached
• protein production

the answer is usually rough endoplasmic reticulum.

2️⃣ Ribosomes make proteins, but rough ER supports and processes them

Ribosomes do the direct assembly of amino acids, while the rough ER helps with:

• protein folding
• modification
• transport

3️⃣ Smooth ER and rough ER have different jobs

• Rough ER → proteins
• Smooth ER → lipids, detoxification, calcium storage

4️⃣ Golgi comes after rough ER

Proteins made on the rough ER are usually sent to the Golgi apparatus for further modification and packaging.

TEAS Exam Memory Trick

Think:

Rough ER = Ribosomes = Proteins

The word rough helps you remember that it has ribosomes attached.

This question is about gas behavior, phase changes, and pressure in a sealed container.

To understand it, we need to understand sublimation and gas pressure.

1. What is Dry Ice?

Dry ice is the solid form of carbon dioxide (CO₂).

Unlike most substances, dry ice does not melt into a liquid under normal atmospheric conditions. Instead, it undergoes sublimation.

Sublimation

Sublimation is the process where a substance changes directly from:

Solid → Gas

without passing through the liquid phase.

Example:

Dry ice (solid CO₂) → CO₂ gas

2. What Happens During Sublimation in a Sealed Container?

When dry ice sublimates:

• Solid CO₂ becomes CO₂ gas molecules
• The number of gas particles increases
• Gas particles spread out and occupy more space

Because the container is sealed, the gas cannot escape.

This leads to:

• More gas molecules moving freely
• More collisions with the container walls

These collisions cause pressure.

3. Why Pressure Increases

Pressure in a container is caused by gas molecules hitting the container walls.

When dry ice sublimates:

1️⃣ More CO₂ molecules enter the gas phase
2️⃣ Gas particles spread out and occupy more volume
3️⃣ The particles collide with the container walls more frequently

More collisions = higher pressure.

Why the Other Options Are Incorrect

Gas CO₂ molecules move faster when CO₂ is a solid.

Molecules in solids move very little.
Gas molecules move much faster than solid molecules, not the other way around.

CO₂ molecules combine to form larger molecules in the gas phase.

CO₂ molecules do not combine during sublimation.
They remain individual CO₂ molecules.

CO₂ particles exert less force on the container walls as a gas.

Gas particles actually exert more force because they move freely and collide with the container walls more frequently.

Key Takeaway Points

1️⃣ Sublimation

Sublimation is the change from:

Solid → Gas

Example: Dry ice → CO₂ gas

2️⃣ Gas pressure

Gas pressure is caused by collisions of gas particles with container walls.

More particles = more collisions = higher pressure

3️⃣ Gas occupies more space than solids

Gas molecules are farther apart and move freely, allowing them to expand and fill available space.

4️⃣ Sealed containers trap gas

When gas is produced in a sealed container, pressure increases because the gas cannot escape.

TEAS Exam Memory Trick

Remember this rule:

More gas particles = More collisions = Higher pressure

This question tests knowledge of anatomical planes, which are imaginary flat surfaces used by anatomists and medical professionals to describe the locations of structures in the body.

The sagittal plane divides the body into left and right portions.

When the sagittal plane runs exactly down the middle, creating equal left and right halves, it is called the midsagittal (median) plane.

When the plane divides the body into unequal left and right portions, it is simply called a parasagittal plane.

Because the question asks which plane divides the body into left and right halves, the correct answer is the sagittal plane.

Major Anatomical Planes of the Body

Understanding anatomical planes is very important in medicine, anatomy, imaging, and surgery.

1. Sagittal Plane

• Divides the body into left and right
• Runs front to back

Special types:

• Midsagittal plane → equal halves
• Parasagittal plane → unequal halves

2. Transverse Plane

Also called the horizontal plane.

• Divides the body into upper (superior) and lower (inferior) parts.
• Used frequently in CT scans and MRI imaging.

Example: separating the head from the torso.

3. Frontal Plane

Also called the coronal plane.

• Divides the body into front (anterior) and back (posterior) halves.

Example: separating the chest from the back.

Note: Frontal plane and coronal plane are the same thing, which is why both appear as answer choices.

Why the Other Options Are Incorrect

Transverse plane

Divides the body into:

• upper (superior)
• lower (inferior)

Not left and right.

Frontal plane

Divides the body into:

• front (anterior)
• back (posterior)

Not left and right.

Coronal plane

The coronal plane is the same as the frontal plane.

It divides the body into:

• front
• back

So it is also incorrect.

Key Takeaway Points

Sagittal plane divides left and right

Think of it as splitting the body down the middle.

Transverse plane divides top and bottom

It creates upper and lower sections.

Frontal (coronal) plane divides front and back

It separates anterior and posterior portions of the body.

Frontal plane = Coronal plane

These terms refer to the same anatomical plane.

Quick TEAS Memory Trick

Use this phrase:

Sagittal → Sides
Transverse → Top and bottom
Frontal → Front and back

This question tests your knowledge of bone classification based on shape and structure.

Bones in the human body are classified into five main categories:

1. Long bones
2. Short bones
3. Flat bones
4. Irregular bones
5. Sesamoid bones

A long bone is characterized by:

• being longer than it is wide
• having a shaft (diaphysis)
• having two expanded ends (epiphyses)
• containing a medullary cavity (bone marrow cavity)

Long bones function primarily to:

• support body weight
• facilitate movement
• act as levers for muscles

The tibia, located in the lower leg, fits all these characteristics and is therefore classified as a long bone.

Structure of a Long Bone

Long bones have several important anatomical parts:

1. Diaphysis

The shaft of the bone.

• made mostly of compact bone
• provides strength and support

2. Epiphysis

The expanded ends of the bone.

• contain spongy bone
• help form joints

3. Medullary Cavity

The hollow center of the diaphysis that contains bone marrow.

4. Articular Cartilage

A smooth tissue covering the ends of bones at joints that reduces friction.

Why the Other Options Are Incorrect

Vertebrae

Vertebrae are classified as irregular bones.

They have complex shapes designed to:

• protect the spinal cord
• support the body
• allow spinal movement

Rib

Ribs are flat bones.

Flat bones:

• protect internal organs
• provide surfaces for muscle attachment

Examples include:

• ribs
• sternum
• skull bones

Carpal

Carpals are short bones found in the wrist.

Short bones:

• are roughly cube-shaped
• provide stability and limited movement

Examples:

• carpals (wrist)
• tarsals (ankle)

Key Takeaway Points

Long bones are longer than they are wide

They have a shaft and two ends.

Long bones help with movement

Muscles attach to them and use them as levers.

Examples of long bones

Common long bones include:

• Femur
• Tibia
• Fibula
• Humerus
• Radius
• Ulna

Bone classification depends on shape

Understanding bone types helps identify their functions in the body.

TEAS Exam Memory Trick

Remember:

Long bones are found in the limbs.

Think:

Arms and legs = long bones

Examples:

• femur
• tibia
• humerus

The original hypothesis says that parasitic worm infestation is damaging to the host. Then the new finding adds an important detail: worm infestation can relieve the effects of certain autoimmune disorders.

That means the hypothesis should not be thrown out completely, but it should be revised to include this newly discovered benefit in some situations.

Choice B is best because it directly matches the new evidence:

• the worms can relieve effects
• relieving effects means they can reduce severity
• this applies to certain autoimmune disorders, not all disorders

Why the other choices are not correct:

A. Lack of worm infestations is the cause of some autoimmune disorders.
This goes too far. The question only says worm infestation can relieve the effects of some autoimmune disorders. It does not say that not having worms causes those disorders.

C. Worm infestations exacerbate the body's immune reactions.
“Exacerbate” means make worse. But the new finding says worm infestation can relieve effects, so this is the opposite of what the evidence supports.

D. Worm infestation prevents the body from immune malfunction.
This is too absolute. The question says worm infestation can relieve the effects of certain autoimmune disorders. It does not say worm infestation completely prevents immune malfunction.

Key Reasoning

When a hypothesis is modified based on new findings, the best answer usually:

• keeps as much of the original idea as possible
• adds only what the new evidence supports
• avoids extreme words like cause, prevents, or always, unless the evidence clearly proves them

Here, the evidence supports a limited revision:
worm infestation may be harmful in general, but it may also reduce the severity of some autoimmune conditions.

Takeaway Points

• A hypothesis should be revised, not automatically discarded, when new evidence appears.
• The best revision is the one that matches the evidence exactly.
• Be careful with extreme answer choices that go beyond the information given.
• In science questions, wording matters:
  • relieve effects = reduce severity
  • not necessarily cause, prevent, or cure

The correct answer is B because bile salts emulsify fats, meaning they break large fat globules into smaller fat droplets. This does not chemically digest the fat by itself, but it makes fat digestion much easier.

What bile salts do

Bile is produced by the liver and stored in the gallbladder. When fatty food enters the small intestine, bile is released. The bile salts in bile help by breaking up large clumps of fat into many smaller droplets.

This process is called emulsification.

Why smaller fat droplets help digestion

Fats do not mix well with water, and digestive enzymes work best when they can reach more surface area of the food being digested.

When bile salts break fat into smaller droplets:

• the surface area of the fat increases
• lipase can act more effectively
• fat digestion becomes faster and more efficient

So bile salts help digestion indirectly by making fats easier for enzymes to digest.

Important Note

Bile salts do not digest fat chemically the way enzymes do. Instead, they physically break up fat into smaller droplets so that pancreatic lipase can digest it more efficiently.

That is why the wording “decrease the size of fat droplets” is the best answer.

Why the Other Choices Are Incorrect

A. Decrease the size of starches to aid in digestion

This is incorrect because bile salts do not act on starches. Starch digestion is mainly done by enzymes such as amylase.

B. Decrease the size of fat droplets to aid in digestion

This is correct because bile salts emulsify fats, breaking large fat globules into smaller droplets.

C. Increase the size of fat droplets to aid in digestion

This is the opposite of what bile salts do. Increasing droplet size would reduce surface area and make digestion harder.

D. Increase the size of starches to aid in digestion

This is incorrect because bile salts do not function in starch digestion, and increasing size would not help digestion.

Core Biology Concept

This question is testing your understanding of the difference between mechanical/physical assistance in digestion and chemical digestion.

• Bile salts help with fat emulsification
• Lipase chemically digests fats
• Amylase digests carbohydrates like starch
• Proteases digest proteins

A useful shortcut:

• Bile = breaks up fat physically
• Lipase = breaks down fat chemically

Take Away Points

• Bile salts emulsify fats by breaking large fat globules into smaller droplets.
• This increases surface area for digestive enzymes.
• Bile helps fat digestion, not starch digestion.
• Bile salts do not chemically digest fat; lipase does that.
• The best way to remember this is: bile breaks fat apart, lipase breaks fat down.

To understand this question, it is important to understand the structure and function of the pancreas, especially the islets of Langerhans, which are clusters of endocrine cells in the pancreas responsible for regulating blood glucose levels.

1. The Islets of Langerhans

The pancreas contains small clusters of hormone-producing cells called islets of Langerhans. These cells release hormones directly into the bloodstream to regulate blood sugar (glucose).

The main cell types in the islets include:

2. Role of Beta Cells

Beta cells produce and release the hormone insulin.

Insulin’s function is to:

• Allow glucose to enter body cells
• Lower blood glucose levels
• Promote energy storage in tissues like muscle and liver

When insulin works properly, glucose moves from the bloodstream → body cells where it can be used for energy.

3. What Happens in Type 1 Diabetes

In Type 1 diabetes mellitus, the body's immune system mistakenly attacks and destroys beta cells in the pancreas.

This is an autoimmune disease.

Because beta cells are destroyed:

• The pancreas cannot produce insulin
• Glucose cannot enter cells
• Blood glucose levels rise dangerously high

As a result, patients must receive external insulin injections, which is why it is called insulin-dependent diabetes.

4. Effects of Beta Cell Destruction

Without insulin:

• Glucose remains in the bloodstream
• Cells are starved of energy
• The body begins breaking down fat and muscle for fuel

Symptoms of type 1 diabetes include:

• Excessive thirst (polydipsia)
• Frequent urination (polyuria)
• Increased hunger (polyphagia)
• Weight loss
• Fatigue

Why the Other Options Are Incorrect

F cells

F cells produce pancreatic polypeptide, which helps regulate digestive enzyme secretion.
They are not responsible for insulin production.

Alpha cells

Alpha cells produce glucagon, a hormone that raises blood glucose levels by stimulating glycogen breakdown in the liver.

Destruction of alpha cells would affect glucose release, not insulin production.

Delta cells

Delta cells produce somatostatin, which inhibits insulin and glucagon release.
They regulate hormone secretion but do not produce insulin.

Key Takeaway Points (Important for TEAS / Nursing Exams)

Beta cells produce insulin

These cells are located in the islets of Langerhans of the pancreas.

Type 1 diabetes is an autoimmune disease

The immune system destroys beta cells, preventing insulin production.

Insulin lowers blood glucose

Insulin allows glucose to enter body cells for energy.

Without insulin, blood sugar rises

High blood glucose is called hyperglycemia.

Patients with type 1 diabetes must take insulin injections for life.

TEAS Exam Memory Trick

Think of this simple rule:

Beta = Blood sugar lowering

So remember:

Beta cells → Insulin → Lowers glucose

If beta cells are destroyed → Type 1 diabetes