IB DP Biology- A2.2 Cell structure - IB Style Questions For SL Paper 2 - New Syllabus
▶️ Answer/Explanation
(a)
The structures labelled I could be mitochondria or lysosomes, as they are membrane-bound organelles. The identification can be supported by considering their approximate size and shape relative to the other structures shown in the diagram.
For example, mitochondria have a characteristic membrane-bound structure and their size and shape differ from other organelles such as the endoplasmic reticulum or Golgi apparatus.
(b)
The fungus is eukaryotic because the diagram shows nuclei. The presence of nuclei indicates that the genetic material is enclosed within a membrane-bound nucleus.
(c)
The main component of the outer structure labelled II is chitin. Fungal cell walls contain chitin, together with other components such as glucans and glycoproteins.
(d)
One atypical feature is that the fungal structure shown is aseptate, meaning it is not divided into separate cells by septa. It can therefore contain more than one nucleus within a continuous cytoplasmic region.
(e)
A water molecule consists of one oxygen atom and two hydrogen atoms. The hydrogen atoms are joined to the oxygen atom by single covalent bonds, and the bonds are arranged at an angle rather than in a straight line.
H–O–H, with the H–O–H bonds arranged at an angle.
