9700 · 1.2
Cells as the basic units of living organisms flashcards
Revision flashcards for Cambridge 9700 Cells as the basic units of living organisms (syllabus 1.2). Flip, recall, then mark a real past-paper question.
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What are the three tenets of the cell theory?
1. All living organisms are composed of one or more cells. 2. The cell is the basic unit of structure and function in organisms. 3. All cells arise from pre-existing cells.
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What is the primary function of the nucleus?
To control the cell's activities by regulating gene expression and to store the cell's genetic material (DNA) within a nuclear envelope.
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State two structural differences between prokaryotic and eukaryotic DNA.
1. Prokaryotic DNA is circular and located in the nucleoid, while eukaryotic DNA is linear and contained within a nucleus. 2. Prokaryotic DNA is 'naked', whereas eukaryotic DNA is associated with histone proteins.
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What is the function of the Golgi apparatus?
To modify, sort, and package proteins and lipids into vesicles for transport to other destinations inside or outside the cell.
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What type of ribosome is found on the Rough Endoplasmic Reticulum (RER) of a eukaryotic cell?
80S ribosomes.
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What is the main function of the smooth endoplasmic reticulum (SER)?
To synthesise, store, and transport lipids and steroids.
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Name two structures present in a typical plant cell but absent in an animal cell.
A cellulose cell wall, a large permanent vacuole, and chloroplasts.
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What is the role of mitochondria?
They are the site of aerobic respiration, where ATP is produced to provide energy for the cell's metabolic activities.
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What is the chemical composition of a prokaryotic cell wall?
Peptidoglycan (also known as murein).