Biology Flashcards

Which organelle is responsible for modifying, sorting, and packaging proteins for secretion?

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.

During which phase of meiosis does crossing over (recombination) occur?

Answer: Prophase I

Crossing over occurs during Prophase I when homologous chromosomes form bivalents and exchange segments at chiasmata.

A population of bacteria doubles every 20 minutes. Starting with 100 bacteria, how many will there be after 1 hour?

Answer: 800

After 1 hour (3 doubling periods): 100 × 2³ = 100 × 8 = 800 bacteria.

Which type of RNA carries the genetic code from the nucleus to the ribosome?

Answer: mRNA

Messenger RNA (mRNA) is transcribed from DNA in the nucleus and carries the codon sequence to ribosomes for translation.

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?

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.

Which enzyme is responsible for unwinding the DNA double helix during replication?

Answer: Helicase

Helicase breaks the hydrogen bonds between base pairs and unwinds the double helix to expose template strands for replication.

In a food web, which organisms occupy the tertiary consumer level?

Answer: Carnivores that eat other carnivores

Tertiary consumers are carnivores that feed on secondary consumers (which themselves feed on primary consumers/herbivores).