Cells and Cell Theory Flashcards
Describe the three principles of cell theory
All living things are made up of one or more cells.
Cells are the most basic unit of structure and function in all living things.
All cells are created by pre-existing cells.
explain the difference between unicellular and multicellular organisms
Unicellular organisms consist of one cell that performs all functions necessary for life.
Multicellular organisms consist of multiple cells with specialised cells that perform specific functions.
Describe the structure and function of prokaryotic cells
Structure: Simple, single-celled organisms without a nucleus; DNA floats freely in the cytoplasm; no membrane-bound organelles.
Function: Carry out all life processes, often as bacteria or archaea.
Compare the similarities between Eukaryotic and Prokaryotic cells
Both have:
A cell surface membrane.
Ribosomes.
DNA.
Cytoplasm.
Explain the key differences between eukaryotic and prokaryotic cells
Eukaryotic cells have a nucleus, while prokaryotic cells lack one. Eukaryotic cells contain larger 80S ribosomes and have membrane-bound organelles, whereas prokaryotic cells have smaller 70S ribosomes and non-membrane-bound organelles. Additionally, the DNA in eukaryotic cells is linear, while prokaryotic cells have circular DNA.
Describe the structure of the plasma membrane
The plasma membrane is a double layer of phospholipids with proteins embedded in it. It regulates the movement of substances into and out of the cell.
explain the role of ribosomes in a cell
Ribosomes are the site of protein synthesis. They can be free-floating in the cytoplasm or attached to the rough endoplasmic reticulum.
describe the function of mitochondria in the cell
Mitochondria are membrane-bound organelles that produce ATP through aerobic respiration. They play a crucial role in energy production, regulation of metabolism, and apoptosis.
Explain the process of protein synthesis in the endoplasmic reticulum and golgi apparatus
Protein synthesis occurs at ribosomes on the rough endoplasmic reticulum (RER).
Proteins are folded and modified inside the RER.
Vesicles transport proteins from the RER to the Golgi apparatus.
In the Golgi apparatus, proteins are further modified, labelled, and packaged into secretory vesicles for transport.
Describe the role of lysosomes in a eukaryotic cell
Lysosomes are membrane-bound organelles containing enzymes that break down biomolecules, old cell parts, foreign particles, and pathogens. They aid in cell renewal and digestion.
Explain the processes of transcription and translation in gene expression
Transcription: DNA is used as a template to create mRNA, a temporary copy of the genetic instructions.
Translation: The mRNA sequence is read by ribosomes to assemble polypeptide chains, creating proteins.
compare the roles of smooth and rough endoplasmic reticulum
Smooth ER: Site of lipid synthesis.
Rough ER: Covered in ribosomes; site of protein synthesis and folding.
