NRE Step 1: Biochemistry Made Simple – Pass with Precision

Vitamins

Vitamins are important helpers for your body. There are two main kinds:

• Fat-soluble vitamins: These stay in your body for a long time. Think of them like a backpack you carry for a while. These are Vitamins A, D, E, and K.
• Water-soluble vitamins: These don’t stay in your body for very long.

Vitamin A has several names, including retinal and Retinol.

• What it does:
  • It’s like a superhero that fights off bad stuff in your body.
  • It helps you see, especially in low light conditions.
  • It keeps your skin and other body coverings healthy.
• When doctors use it:
  • To help with a type of blood cancer called leukemia.
  • When kids have measles.
  • For skin problems like acne.
• If you don’t have enough:
  • You might have trouble seeing at night.
  • You can get dry spots on your eyes.
  • Your eyes might get sick.
• Who should be careful: Pregnant women should not take too much Vitamin A.

Vitamin D is also called Calcitriol.

• Where it comes from: Sunlight is a great source!
• How it works:
  • Your liver and kidneys help turn sunlight into active Vitamin D.
  • It helps your body soak up calcium from the food you eat, which makes your bones strong.
  • If you have enough Vitamin D, it helps build strong bones.
  • If you don’t have enough, your body might take calcium from your bones, making them weak.
• If you don’t have enough:
  • In kids, Bones can become soft and bendy, leading to bowed legs. This is called Rickets.
  • In adults, Bones can hurt. This is called Osteomalacia.
  • Kidney problems can also cause bone issues.
  • Your muscles might feel weak.

Vitamin E is also called Tocopherol.

• What it does: It protects your red blood cells from getting hurt.
• If you don’t have enough:
  • Your red blood cells can break too easily. This is called Hemolytic Anemia.
  • You might have trouble walking straight.
  • Babies can get a tummy problem.
  • But it does NOT cause a special type of anemia called Megaloblastic anemia.

Vitamin K

• Where it comes from: Your gut makes some of it.
• What it does: It helps your blood clot when you get a cut.
• If you don’t have enough:
  • You might bleed more easily.
  • Tests that check how fast your blood clots will show that it takes too long.
• Important for babies: Babies get Vitamin K so they don’t bleed too much.
• Taking too many antibiotics can sometimes mess up Vitamin K.

Water-Soluble Vitamins

Vitamin B1 (Thiamine) is found in the outer part of rice.

• What it does: It helps your body use sugar for energy.
• If you don’t have enough:
  • You can get a sickness called Beriberi.
    • Dry Beriberi: Makes your muscles weak.
    • Wet Beriberi: Affects your heart.
  • It can also cause brain damage called Wernicke-Korsakoff syndrome. This can make you confused, have strange eye movements, and trouble walking.
    • Wernicke is often from not enough vitamins in your food.
    • Korsakoff is often from drinking too much alcohol and not getting enough vitamins.

Vitamin B2 (Riboflavin)

• If you don’t have enough:
  • Your eyes might get red.
  • You can get sores around your mouth.

Vitamin B3 (Niacin) It can help lower bad fats in your blood. Your body can make it from a special building block called Tryptophan.

• If you don’t have enough:
  • You can get a sickness called Pellagra.
  • This causes:
    • Rashes on your skin.
    • Diarrhea (tummy troubles).
    • Dementia (trouble thinking clearly).
  • It can also cause gut problems and hair loss.

Vitamin B6 (Pyridoxine)

• What it does: It helps your body make important brain chemicals like Dopamine and Serotonin. It also helps keep the protective covering around your nerves healthy.
• Important note: A medicine called INH can stop Vitamin B6 from working.

Vitamin B7 (Biotin)

• If you don’t have enough: Eating too many raw egg whites can cause problems.

Folic Acid

• If you don’t have enough: You can get a type of anemia where your red blood cells are too big. But it does NOT cause nerve problems.

Vitamin B12 (Cobalamin)

• If you don’t have enough:
  • You can get the same big red blood cell anemia as Folic Acid deficiency.
  • BUT, you WILL also have nerve problems. This is because it can hurt the protective covering of your nerves.
• Who might not have enough: People who are strict vegetarians, have had stomach surgery, or have certain stomach problems. Some medicines can also lower it.

Vitamin C (Ascorbic Acid)

• What it does: It helps your body make collagen. Collagen is a glue-like substance that holds your body together.
• It also helps: Your body take in iron.
• If you don’t have enough:
  • You can get a sickness called Scurvy.
  • This causes your gums to bleed.

Protein Energy Malnutrition This happens when you don’t get enough food, especially protein.

• Kawashiorkor: This happens when you don’t get enough protein.
  • You can get swelling because your body can’t hold water properly.
  • You might have a fatty liver and skin problems.
• Marasmus: This happens when you don’t get enough calories (energy).
  • Your muscles will waste away, making you very thin.

Collagen Collagen is the most common protein in your body.

• Different types of collagen are found in:
  • Bones and teeth (Type 1).
  • Cartilage (Type 2).
  • Healing skin and babies (Type 3).
  • The thin layer that supports your body’s tissues (Type 4).

Osteogenesis Imperfecta This is a problem where your body doesn’t make enough Type 1 collagen.

• What happens:
  • Your bones are weak and break easily.
  • The white part of your eyes might look blue.

Goodpasture Syndrome This is when your body’s defense system attacks Type 4 collagen. It mostly hurts your kidneys and lungs.

Important Enzymes (Body Helpers) These are like special workers that control how fast things happen in your body.

• In breaking down sugar: Phosphofructokinase 1 (PFK-1).
• In making energy: Isocitrate dehydrogenase.
• In making energy from fats: Hydroxymethylglutarate HMG-CoA reductase.
• In making cholesterol: HMG-CoA reductase.
• In making glycogen (stored sugar): Glycogen Synthase.
• In breaking down glycogen: Glycogen Phosphorylase.
• In making urea (body waste): Carbomyophosphase 5-1 (CPS-1).

Glycogen Storage Diseases These are problems where your body can’t properly store or use glycogen (stored sugar).

• Glucose-6-phosphatase deficiency (Gierke’s disease):
  • Causes very low blood sugar.
  • Your liver gets big.
  • You can have problems with uric acid and fats in your blood.
• Debranching enzyme error (Corri disease): Another problem with breaking down glycogen.
• Acid maltase error (Pompe disease): Affects glycogen breakdown in a different way.
• Branching enzyme error (Anderson disease): Causes long chains of glycogen to build up.
• Glycogen phosphorylase error (Hers’s disease in liver, McArdle disease in muscle): Problems breaking down glycogen in the liver or muscles.

Muscle Diseases (Muscular Dystrophies)

• Duchenne Dystrophy:
  • This is passed down from the mother.
  • The body is missing a very important muscle protein called Dystrophin.
  • Kids might use their hands to push themselves up to stand (Gower’s sign).
  • Their calf muscles might look big, but it’s mostly fat.
  • It usually starts before age 5.
  • Sadly, kids often don’t live very long, and the heart muscle can become weak.
• Becker Dystrophy:
  • Similar to Duchenne, but the Dystrophin protein is only partly missing.
  • It starts later, in teenage years.
  • People usually have a better outcome than with Duchenne.
• Myotonic Dystrophy:
  • This is passed down from either parent.
  • It usually starts when people are 20-30 years old.
  • One sign is that if you shake someone’s hand, they might have trouble letting go.
  • Other signs include cloudy eyes, hair loss on the front of the head, and problems with reproductive organs.

Chromosome Problems

• Patau Syndrome (Trisomy 13): Babies often have problems with their brain not forming fully, small heads, extra fingers or toes, and kidney cysts. They usually don’t live past 1 year.
• Edward Syndrome (Trisomy 18): Babies often have low-set ears, small jaws, and other problems.
• Down Syndrome (Trisomy 21): Babies often have a single crease across their palm, problems with their gut, and flat faces. They can also have a higher chance of certain blood cancers.

Amino Acid Problems Amino acids are the building blocks of proteins.

• Phenylalanine problems:
  • Phenylketonuria (PKU): If you can’t break down Phenylalanine, it builds up in your body.
    • This can lead to small head size, learning problems, a “musty” smell in your pee, and seizures.
  • Alkaptonuria: If you can’t break down Homogentisic acid (a step after Phenylalanine), your pee turns black when it sits out. It can also cause dark spots in your body and joint pain.
  • Albinism: If you can’t make melanin (color) from Tyrosine, you have very pale skin, hair, and eyes.

Maple Syrup Urine Disease This is a problem where your body can’t break down certain amino acids.

• Signs: Vomiting and brain problems. Your pee might smell like maple syrup.

Lipoproteins These are like tiny packages that carry fats (lipids) and proteins in your blood.

• Chylomicrons: Carry fats from the food you eat to your body.
• VLDL (Very Low-Density Lipoprotein): Carries fats made in your liver to your body.
• LDL (Low-Density Lipoprotein): Often called “bad” cholesterol. It carries cholesterol from your liver to your body.
• HDL (High-Density Lipoprotein): Often called “good” cholesterol. It carries cholesterol from your body back to your liver.

Ketone Bodies When your body doesn’t have enough sugar for energy, it can make ketone bodies from fat.

• They make your body acidic.
• They are a backup energy source for your brain.
• Diabetic Ketoacidosis (DKA): This happens when people with diabetes don’t have enough insulin. Their body makes a lot of ketone bodies, which makes the blood acidic. They might breathe fast and their breath can smell like acetone (nail polish remover).

Marfan Syndrome This is a problem with the body’s connective tissue, which holds everything together.

• It’s caused by a problem on chromosome 15.
• People are often tall and thin, with very long arms and legs.
• They can have problems with their eyes (lens dislocation) and heart (aortic dissection).

Fragile X Syndrome This is a problem on the X chromosome.

• It’s caused by a mistake in a gene.
• People often have learning difficulties, a long face, and a prominent chin.

Diseases from Repeating Genes Some diseases happen when a small piece of DNA is repeated too many times.

• Fragile X Syndrome (repeated CGG).
• Huntington Disease (repeated CAG).
• Myotonic Dystrophy (repeated CTG).
• Friedreich Ataxia (repeated GAA).

Urea Cycle This is how your body gets rid of ammonia, which can be poisonous.

• CPS-1: An important helper in this cycle.
• If CPS-1 is not working: Ammonia builds up, causing confusion, shaking hands, slurred speech, vomiting, and swelling in the brain.
• Treatment: Medicines like Lactulose can help.