Cell Theory
Who observed cork and introduced the word “cells”?
Robert Hooke.
Which type of cell does not have a nucleus?
A prokaryotic cell.
Which organelle contains DNA and directs many activities of a eukaryotic cell?
The nucleus.
Which supporting structure is found outside the membrane of plant cells but not animal cells?
The cell wall.
A cell needs a lot of energy for its activities. Which organelles would you expect it to contain many of?
Mitochondria.
Which scientist concluded that plants are made of cells?
Matthias Schleiden.
Where is the main DNA found in a prokaryotic cell?
In the nucleoid region of the cytoplasm, not enclosed in a nucleus.
Which structures make proteins?
Ribosomes.
Which organelle allows photosynthetic plant cells to carry out photosynthesis?
The chloroplast.
A cell needs to control which substances enter and leave. Which structure is responsible?
The cell membrane.
Which scientist is commonly credited with the statement that all cells come from pre-existing cells?
Rudolf Virchow.
Name two structures or components found in both prokaryotic and eukaryotic cells.
Any two: cell membrane, cytoplasm, ribosomes, DNA.
Which organelle modifies, sorts and packages proteins?
The Golgi apparatus.
Name two structures found in both typical plant and animal cells.
Any two: nucleus, mitochondria, cell membrane, cytoplasm, ribosomes, ER, Golgi apparatus.
A scientist sees a cell with a nucleus and many membrane-bound organelles. Is it prokaryotic or eukaryotic?
Eukaryotic.
Outline the three main ideas of cell theory. Use one idea to explain how new cells form as an organism grows.
Living things consist of one or more cells; the cell is the basic unit of life; cells come from pre-existing cells. Growth involves existing cells dividing to produce new cells.
Outline TWO differences between prokaryotic and eukaryotic cells.
Prokaryotes lack a membrane-bound nucleus; eukaryotes have one. Prokaryotes lack membrane-bound organelles; eukaryotes have them.
For a protein destined for secretion, put these in order and outline each role: Golgi apparatus, ribosome on rough ER, rough ER.
Ribosome on rough ER makes the protein; rough ER helps fold/process it and sends it in transport vesicles; Golgi modifies, sorts and packages it for delivery.
Outline THREE structural differences between typical photosynthetic plant cells and animal cells.
Plant cells have a cell wall; animal cells do not. Photosynthetic plant cells have chloroplasts; animal cells do not. Mature plant cells typically have a large central vacuole; animal cells lack this large central vacuole, though small vacuoles may occur. Not every plant cell has chloroplasts.
Cell X has no nucleus or membrane-bound organelles. Cell Y has a nucleus and many membrane-bound organelles. Which has greater internal compartmentalisation? Outline your reasoning using the observations.
Cell Y: its nucleus encloses DNA and its membrane-bound organelles create specialised compartments for different functions. Cell X lacks these membrane-bound compartments.
Outline how TWO scientists contributed to the development of cell theory.
For example, Hooke observed cork and named its compartments “cells”; Schleiden concluded that plants are made of cells. Accept Schwann: animals are made of cells, or Virchow: cells arise from existing cells. Require two scientists and their contributions.
A cell has circular DNA, ribosomes, no nucleus and no membrane-bound organelles. Identify the cell type and justify your answer using TWO pieces of evidence.
Prokaryotic: it lacks a nucleus and membrane-bound organelles. Circular main DNA also supports this classification; ribosomes alone do not distinguish the types.
A cell can still make proteins, but its Golgi apparatus stops working properly. Predict what may happen to those proteins and explain why.
Proteins passing through the Golgi may not be properly modified, sorted or packaged, so delivery to their correct destinations or secretion may be disrupted.
Cell A has chloroplasts, a cell wall and a large central vacuole. Cell B lacks these. A student says Cell A is better adapted to make its own food. Explain using at least TWO structures.
Chloroplasts absorb light for photosynthesis to make sugars. The central vacuole stores water and helps maintain turgor against the supporting cell wall. These support the cell, but chloroplasts directly carry out photosynthesis; the wall and vacuole do not make food. Require two accurate structure–function links.
A cell has ribosomes, rough ER and a Golgi apparatus, but its mitochondria are badly damaged. Predict how this could affect the whole cell even though the other organelles are present.
Less ATP may be available from aerobic respiration. Protein synthesis, processing and transport require energy, so they may slow or become disrupted. Organelles depend on energy supply as well as being physically present.