EmSAT Biology 4 — Questions and Answers
Question 1: Which organelle is responsible for modifying, sorting, and packaging proteins for secretion?
- Rough endoplasmic reticulum
- Golgi apparatus (Correct answer)
- Lysosome
- Peroxisome
Correct answer: Golgi apparatus
The Golgi apparatus receives proteins from the ER, modifies them, and packages them into vesicles for export or delivery to other organelles.
Question 2: During which phase of meiosis does crossing over (recombination) occur?
- Metaphase I
- Prophase I (Correct answer)
- Anaphase II
- Telophase II
Correct answer: Prophase I
Crossing over occurs during Prophase I when homologous chromosomes form bivalents and exchange segments at chiasmata.
Question 3: A population of bacteria doubles every 20 minutes. Starting with 100 bacteria, how many will there be after 1 hour?
- 400
- 600
- 800 (Correct answer)
- 1000
Correct answer: 800
After 1 hour (3 doubling periods): 100 × 2³ = 100 × 8 = 800 bacteria.
Question 4: Which type of RNA carries the genetic code from the nucleus to the ribosome?
- tRNA
- rRNA
- mRNA (Correct answer)
- snRNA
Correct answer: mRNA
Messenger RNA (mRNA) is transcribed from DNA in the nucleus and carries the codon sequence to ribosomes for translation.
Question 5: What is the term for the movement of water across a semi-permeable membrane from a region of low solute concentration to high solute concentration?
- Active transport
- Facilitated diffusion
- Osmosis (Correct answer)
- Endocytosis
Correct answer: Osmosis
Osmosis is the passive movement of water across a semi-permeable membrane from a hypotonic (low solute) to a hypertonic (high solute) region.
Question 6: Which enzyme is responsible for unwinding the DNA double helix during replication?
- DNA polymerase
- Ligase
- Helicase (Correct answer)
- Primase
Correct answer: Helicase
Helicase breaks the hydrogen bonds between base pairs and unwinds the double helix to expose template strands for replication.
Question 7: In a food web, which organisms occupy the tertiary consumer level?
- Plants that fix nitrogen
- Herbivores that eat grass
- Carnivores that eat other carnivores (Correct answer)
- Decomposers that break down dead matter
Correct answer: Carnivores that eat other carnivores
Tertiary consumers are carnivores that feed on secondary consumers (which themselves feed on primary consumers/herbivores).
EmSAT Biology 4
Which organelle is responsible for modifying, sorting, and packaging proteins for secretion?