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B2.2.6 (HL)—Nuclear membrane benefits

The nuclear envelope is a double membrane that supports regulated nuclear exchange and can reorganize into vesicles during cell division.

Syllabus
First assessment 2025
Objective
B2.2.6
Level
HL

Exam analysis

Chance of appearing1%of analysed past papers
Latest appearanceNovember 2025
Most common paperPaper1A
Typical marks1

Common command terms

  • Identify

Recent exam appearances

November 2025Paper1A ["HL"] · TZ316[ 1 ]B2.2.6 (HL)—Nuclear membrane benefits
Practice this objective

Coverage 2025–2025 · Updated 15 Jul 2026

A Nuclear Envelope Controls Exchange

HL only

The nuclear envelope is a double membrane that separates nucleoplasm from cytoplasm while nuclear pores provide rapid, regulated exchange.

Compartmentalization protects DNA and permits RNA processing before translation. Pores selectively export RNA and import nuclear proteins, while the nuclear lamina supports envelope shape and chromosome organization.

During mitosis and meiosis in many eukaryotic cells, the envelope breaks into membrane vesicles or fragments so spindle microtubules can access chromosomes; it re-forms around daughter nuclei later.

Mature mRNA exits through a pore, whereas a transcription factor bearing a nuclear-localization signal can be selectively imported.

The envelope is neither freely permeable nor permanently intact. Pores enable controlled interphase exchange, and regulated disassembly supports nuclear division.

Nuclear membrane benefits

HL only

Assessment in practice

1 marks
How it is assessed

This objective is assessed through multiple choice, commonly using Identify.

Command terms

Identify

What earns marks

Build the answer around this relationship: The nuclear envelope is a double membrane around the nucleus.

Representative question

Question 1

[Maximum number: 1]

What is a benefit of double membranes surrounding the nuclei of eukaryotic cells?

A

They reduce the surface area of the nucleus.

B

They can easily break down into vesicles during mitosis.

C

Hydrophilic phospholipid tails can be kept away from the cytoplasm.

D

Pores are formed to allow movement of DNA from the nucleus to the cytoplasm.

Link Organelle Structure To Function

HL only

HL structure-function answers should link organelle compartments to the process they support. Mitochondria use cristae, intermembrane space, and matrix; chloroplasts use thylakoid membranes, thylakoid space, and stroma. Protein export is a route: rough ER makes entry-pathway proteins, Golgi modifies and sorts, vesicles bud and fuse with targets.

  • Mitochondrion: cristae/inner membrane for ATP synthase, intermembrane space for protons, matrix for Krebs cycle enzymes.
  • Chloroplast: thylakoid membranes for photosystems/ATP synthase, thylakoid space for protons, stroma for Calvin cycle enzymes.
  • Secretory pathway: rough ER to Golgi to vesicle to plasma membrane or another target.

Concept essentials

  • The nuclear envelope is a double membrane around the nucleus.
  • Nuclear pores regulate exchange between nucleus and cytoplasm.
  • The envelope can break down into vesicles during mitosis.
  • Chromosomal DNA remains in the nucleus rather than moving through pores for translation.