• Describe the basic structure and function of the nucleus.
• Describe the structure of the nuclear pore complex and its role in nucleo-cytoplasmic
exchange.
• Describe the organisation of DNA within the nucleus.
• Outline the functional differences between euchromatin and heterochromatin.
Its inner surface is lined nuclear lamina, which is made of intermediate filaments.
Fluid within the lumen of the nucleus maintains its spherical shape.
Intermediate filaments aid in organising and packing chromatin.
Question 4
Question
What is the consequence of a dysfunctional nuclear lamina? (Choose all correct.)
Answer
Abnormally shaped nuclei
Progeria syndrome
Cystic fibrosis
Cerebral palsy
Poor mitogenesis/meiosis
Accelerated ageing
Slow development
Question 5
Question
Choose the incorrect statement about the nuclear pores.
Answer
They allow mRNA, rRNA, and tRNA to exit.
It allows control signals into the nucleus.
It mediates passage into and out of the nucleus.
Energy and cellular materials move out of the nucleus.
Question 6
Question
How much DNA is in the human nucleus?
Answer
2.5 cm
2.5 m
25 cm
Question 7
Question
DNA is packed in the nucleus so that it is inaccessible until replication.
Answer
True
False
Question 8
Question
The DNA double helix is about [blank_start]2[blank_end]nm in diameter. Bundled into [blank_start]nucleosomes[blank_end] or "beads" using [blank_start]H2a, H2b, H3, and H4[blank_end] histone proteins, it is about [blank_start]10[blank_end]nm in diameter. Further interaction with [blank_start]H1[blank_end] histone proteins [blank_start]coils[blank_end] this into a [blank_start]30[blank_end]nm fibre. During replication this can be [blank_start]looped[blank_end] to form a [blank_start]300[blank_end]nm diameter [blank_start]chromosome[blank_end].
Answer
2
nucleosomes
H2a, H2b, H3, and H4
10
H1
30
looped
coils
300
metaphase chromosome
interphase chromosome
Question 9
Question
Which kind of chromatin is the denser, inactive form?
Answer
heterochromatin
euchromatin
Question 10
Question
The ratio of heterochromatin and euchromatin stays static during a cell's lifetime.
Answer
True
False
Question 11
Question
The location of chromosomes in the nucleus is not random.