2.4 Eukaryotic cells Flashcards
What are the 2 types of organisms?
Prokaryotes and eukaryotes
Define metabolism
The sum of all chemical reactions that take place within each cell of a living organism and that provide energy for vital processes and for synthesizing new organic material
Where do reactions take place within a cell?
The cytoplasm
What separates the cytoplasm of eukaryotic cells from the cell’s external environment?
Cell-surface membrane / plasma membrane
Define organelle.
What is their function?
Compartments with varying functions inside eukaryotic cells
Provide specific environments and therefore specific conditions for different cellular reactions.
What is the nucleus?
What is the function of the nucleus and how does it carry this out?
Large organelle surrounded by a nuclear envelope.
Contains DNA molecules
Controls the cell’s activity by controlling the transcription of DNA
What is the function of DNA?
Directs the synthesis of proteins required for the cell (but remember protein synthesis occurs in ribosomes)
What does the nuclear envelope contain?
What is the function of this?
Nuclear pores - allow substances to move into and out of the nucleus
How is DNA inside the nucleus transferred outside of the nucleus?
DNA is transcribed into smaller RNA molecules, because DNA itself is too big to leave the nucleus, and the RNA molecules are then exported via nuclear pores
How is chromatin formed?
When DNA associates with histones
Define histones
Proteins that form a complex with DNA called chromatin
How are chromosomes formed?
When chromatin coils and condenses
What is the nucleolus?
What is the function of the nucleolus?
What is the nucleolus composed of?
- An area within the nucleus
- Produce ribosomes
- RNA and proteins
Describe the structure of mitochondria
• Double membrane:
- Inner membrane highly folded, forms cristae
- Membrane forming the cristae contains enzymes used in aerobic respiration
• Fluid interior known as matrix
• Contain DNA - mtDNA (mitochondrial DNA) + ribosomes
What is the function of mitochondria?
Site of aerobic respiration, where ATP is produced
• Can produce their own enzymes and reproduce themselves
Where are mitochondria found in high numbers?
In active cells