1.2 Flashcards
What are the three major nutrient groups that living things are composed of?
- Carbohydrates
- Lipids
- Proteins
Examples include sugars and starch for carbohydrates, oil and butter for lipids, and meat and cheese for proteins.
What is the primary function of proteins in a cell?
Building the structural components of a cell
Proteins are not primarily used for energy but for growth, repair, and cell division.
How many different amino acids are used to build proteins?
20 different amino acids
What governs the control of protein synthesis in a cell?
The nucleus of the cell
The nucleus acts like ‘City Hall’ in a town, overseeing cellular activities.
What is DNA an abbreviation for?
Deoxyribonucleic Acid
What are the exceptions to cells that contain a nucleus?
- Red Blood Cells (no nucleus when mature)
- Sex Cells (Sperm and Egg, only have ½ the amount of DNA)
What is the only molecule known that can replicate itself?
DNA
What form does DNA usually take when not in cell division?
Chromatin
How many chromosomes do humans have in each cell?
46 chromosomes
What is a gene?
A section of a chromosome that codes for a certain protein
What three types of molecules make up a nucleotide?
- A 5 carbon sugar called deoxyribose
- A phosphate group
- One of four types of nitrogenous bases
What are the two categories of nitrogenous bases in DNA?
- Purines (Adenine and Guanine)
- Pyrimidines (Thymine and Cytosine)
What is Complementary Base Pairing?
Adenine always bonds to Thymine, and Guanine always bonds to Cytosine
This specific bonding ensures proper DNA structure.
What holds the two complementary bases together in the DNA molecule?
Weak Hydrogen bonds
What structure does DNA form due to its complementary strands?
A double helix
Fill in the blank: The alternating sugar and phosphates in DNA make up the _______.
rails (backbone)
True or False: A purine base can bond with another purine base.
False
What happens to chromatin during cell division?
It bunches up to form chromosomes
