Intro to Living Cell

Question 1

Define a living cell

Answer 1

• Fundamental unit of all living things on Earth.
• Takes nutrients & free E from surroundings
• Make copies of themselves.

Question 2

Smallest known cell + size

Answer 2

mycoplasma genitalium

0.3μm

Question 3

Largest cell + size

Answer 3

ostrich egg

20cm

Question 4

Key universal features of all living cells (9)

Answer 4

1. Plasma membrane
2. Exchange of molecules with surroundings
3. Communication
4. Genetic information stored as DNA
5. Gene expression
6. Protein synthesis
7. Compartmentalisation of eukaryotic cells
8. Life as a ‘pattern in flux’
9. Evolution from a common ancestor

Question 5

xplain the concept of life as “a pattern in flux”

Answer 5

constituent molecules in living cells are constantly being exchanged/replaced.
Overall structure of cell/organism remains the same due to homeostasis.

Question 6

Define homeostasis

Answer 6

the ability/tendency of an organism or cell to maintain internal eqm by adjusting its physiological processes.

Question 7

Define taxonomy

Answer 7

academic discipline of defining groups of biological organisms on the basis of shared characteristics

Question 8

Define Phylogenetics

Answer 8

study of evolutionary relationships among groups of organisms

Question 9

State the 3 major domains of living world

Answer 9

bacteria
archaea
eukaryotes

Question 10

Explain how cells communicate

Answer 10

• extracellular signal molecule binds to receptor proteins on the plasma membrane of the cell.
• Receptor proteins transmit signal into intercellular signalling proteins.
• Effector proteins (e.g. metabolic enzymes, gene regulatory proteins, cytoskeletal proteins) then causes a change (e.g. altered metabolism, altered gene expression or altered cell shape or movement)