Exam 3 (Protein Synthesis)

Question 1

How are alleles, DNA, chromosomes, genes, and protein synthesis connected?

Answer 1

DNA is the molecule that stores genetic information.

Chromosomes are long strands of DNA packed together.

Genes are sections of DNA on chromosomes that code for proteins.

Alleles are different versions of a gene.

During protein synthesis, the gene’s DNA is used to build proteins, which determine traits.

Question 2

Where does transcription happen, and what is made?

Answer 2

In the nucleus, DNA is transcribed into mRNA.

Question 3

What happens at the ribosome during protein synthesis?

Answer 3

The ribosome reads mRNA and assembles amino acids into a protein.

Question 4

What does the rough ER do in protein production?

Answer 4

It helps fold and modify the new protein.

Question 5

What is the function of the Golgi apparatus?

Answer 5

It packages and ships proteins to their destination.

Question 6

What do vesicles do in protein transport?

Answer 6

They carry proteins through the cell or to the outside of the cell.

Question 7

What is the function of the nucleus?

Answer 7

Stores DNA and controls the cell’s activities

Question 8

What do ribosomes do?

Answer 8

Build proteins by reading mRNA.

Question 9

What is the endoplasmic reticulum (ER)?

Answer 9

Rough ER has ribosomes and helps fold and modify proteins.

Smooth ER makes lipids and detoxifies substances.

Question 10

What is the function of the Golgi apparatus?

Answer 10

Sorts, packages, and ships proteins and other materials.

Question 11

What do mitochondria do?

Answer 11

Make energy (ATP) from food through cellular respiration.

Question 12

What are lysosomes?

Answer 12

Break down waste, old cell parts, and invaders (contain enzymes).

Question 13

What are vacuoles used for?

Answer 13

Store water, nutrients, or waste. (Large in plant cells.)

Question 14

What does the cell membrane do?

Answer 14

Controls what enters and leaves the cell; provides structure.

Question 15

What is the cytoplasm?

Answer 15

Jelly-like fluid where organelles are suspended.

Question 16

What is the cytoskeleton?

Answer 16

Network of fibers that gives shape and helps move organelles.

Question 17

What organelle is only in plant cells and helps with photosynthesis?

Answer 17

Chloroplasts – they convert sunlight into food (glucose).

Question 18

What is the cell wall and which cells have it?

Answer 18

A rigid outer layer that supports and protects plant cells.

Question 19

What is the function of proteins in the body?

Answer 19

Proteins build and repair tissues, act as enzymes, transport substances, fight disease, and support cell structure.

Question 20

What is the structure of a protein?

Answer 20

Proteins are made of chains of amino acids folded into complex shapes. The shape determines the protein’s function.

Question 21

Why are proteins important in our diet?

Answer 21

We eat proteins to get amino acids, which the body uses to build its own proteins.

Question 22

What happens to amino acids once they enter the cell?

Answer 22

Amino acids are directed to ribosomes, where they are used to build proteins.

Question 23

What is transcription in protein synthesis?

Answer 23

In the nucleus, DNA is copied into mRNA.

Question 24

What is translation in protein synthesis?

Answer 24

In the ribosome, mRNA is read and used to assemble a chain of amino acids into a protein.

Question 25

What is protein processing?

Answer 25

After translation, proteins are folded and modified in the rough ER and sent to the Golgi apparatus for packaging.

Question 26

What is the function of enzymes?

Answer 26

Enzymes speed up chemical reactions without being used up.

Question 27

What does the enzyme ribosome do?

Answer 27

Ribosomes are not enzymes but act like one by assembling amino acids into proteins during translation.

Question 28

What does the enzyme lactase do?

Answer 28

Lactase breaks down the sugar lactose into glucose and galactose so your body can digest dairy.

Question 29

Where does lactase persistence or nonpersistence occur in the small intestine, and what happens?

Answer 29

In the lining of the small intestine, cells produce the enzyme lactase. In people with lactase persistence, these cells keep making lactase into adulthood, so lactose is broken down and absorbed normally. In people with lactase nonpersistence, the enzyme stops being made after childhood, so lactose isn’t digested, leading to gas, bloating, and discomfort when they eat dairy.

Question 30

What are the steps of lactase persistence and nonpersistence?

Answer 30

Lactase Persistence (can digest lactose): Lactose enters the small intestine. Cells in the intestinal lining produce lactase enzyme. Lactase breaks down lactose into glucose and galactose. These sugars are absorbed into the bloodstream for energy. No digestive issues occur. Lactase Nonpersistence (lactose intolerant): Lactose enters the small intestine. Little or no lactase enzyme is made. Lactose isn’t broken down. Undigested lactose travels to the large intestine. Bacteria ferment it, causing gas, bloating, and discomfort.

Question 31

How does changing the amount of enzyme in the small intestine affect tonicity and osmosis?

Answer 31

More enzyme (like lactase) → more lactose is broken down into absorbable sugars → fewer large molecules left behind → less water drawn into the intestine → normal water balance. Less enzyme → lactose stays undigested → increases solute concentration in the intestine → makes the inside hypertonic → water moves in by osmosis → causes diarrhea or bloating.

Question 32

How do you use a pedigree and Punnett square to predict lactase persistence (LP), and which allele causes it?

Answer 32

Lactase persistence (LP) is an autosomal dominant trait. The T allele = lactase persistence (dominant) The t allele = lactase nonpersistence (recessive) People with TT or Tt genotypes have LP. Only tt individuals are lactose intolerant. Using a pedigree: Track LP and non-LP traits across generations. LP individuals must have at least one T. Non-LP individuals must be tt. Using a Punnett square: Cross parents’ genotypes to predict the probability of LP or non-LP children.