2.1 Cell structure Flashcards
The function of the nucleus
- Act as the control centre of the cell through the production of mRNA and tRNA and hence protein synthesis
- Retain the genetic material of the cell in the form of DNA and chromosomes
- Manufacture ribosomal RNA and ribosomes
The structural features of a nucleus
- Nuclear envelope
- Nuclear pores - allows large molecules out
- Nucleoplasm
- Chromosomes- consist of protein-bound, linear DNA
- Nucleolus - manufactures ribosomal RNA and assembles ribosomes
The function of a mitochondrion
Site of aerobic respiration and produces ATP
The structural features of a mitochondrion
- Double membrane
- Cristae
- Matrix
The function of chloroplasts
Carry out photosynthesis
Structural features of a chloroplast
- Chloroplast envelope
- Grana (stacks of thylakoids)
- Stroma
-Starch grains
Function of RER
- Provide a large SA for the synthesis of proteins and glycoproteins
- Provides a pathway for the transport of materials throughout the cell
Function of SER
- Synthesise, store and transport lipids and carbohydrates
Function of Golgi body (5 things)
- Add carbohydrate to protein to form glycoproteins
- Produce secretory enzymes
- Secrete carbohydrates
- Transport, modify and store lipids
- Form lysosomes
Function of lysosomes
- Hydrolyse material ingested by phagocytic cells
- Release enzymes to the outside of the cell (exocytosis)
- Digest worn out organelles (autophagy)
- Autolysis (completely break down cells )
Function of ribosomes
Protein synthesis
What ribosomes are found in animal cells
80S
Where are 70S ribosomes found
Prokaryotic cells, mitochondria and chloroplasts
Function of a cell wall
- Provide mechanical support from osmotic entry
- To provide mechanical support as a whole
- To allow water to pass along it
What are cell walls of plants and algae made of
Cellulose
What are cell walls of fungi made of
Chitin
What is the boundary between 2 adjacent cell walls called
Middle lamella
Function of plant vacuoles
- Make a cell turgid
- Sugars and amino acids may act as a temporary food store
- Pigment may attract pollinators
What is the cell wall of a bacteria made of
Murein
How do bacteria store food
As glycogen granules and oil droplets
What form is the genetic material of bacteria
Circular strands of DNA
Role of a capsule
Protects bacterium from other cells and helps groups of bacteria to stick together for further protection
Describe 2 functions of the golgi apparatus in a eukaryotic cell (2 marks)
- Modify/ package/ transport proteins
- Modify/ package/ transport lipids
- Forms vesicles
Describe the structure and function of the nucleus (4 marks)
Structure
1. Nuclear envelope and pores
OR
Double membrane and pores;
2. Chromosomes/chromatin
OR
DNA with histones;
3. Nucleolus/nucleoli;
Function
4. (Holds/stores) genetic information/material
for polypeptides (production)
OR
(Is) code for polypeptides;
5. DNA replication (occurs);
6. Production of mRNA/tRNA
OR
Transcription (occurs);
7. Production of rRNA/ribosomes;
Give 2 features of all prokaryotic cells that are not features of eukaryotic cells (1 mark)
No membrane-bound organelles/correct
example
OR
(Single,) circular/loop DNA (in cytoplasm)
OR
DNA free in cytoplasm
OR
DNA not associated with proteins/histones
OR
Murein/peptidoglycan (in) cell wall;
Describe how a sample of chloroplasts could be isolated from leaves (4 marks)
- Break open cells/tissue and filter
OR
Grind/blend cells/tissue/leaves and filter; - In cold, same water potential/concentration, pH
controlled solution; - Centrifuge/spin and remove nuclei/cell debris;
- (Centrifuge/spin) at high(er) speed, chloroplasts
settle out;
What is the component of the cell wall of algae
Cellulose
What is the component of the cell wall of fungi
Chitin
