Cell structure and Organisation- Unit 1.2 Flashcards
What does the nucleus do?
Contains DNA to code for protein synthesis. DNA replication occurs here and transcription produces mRNA templates.
What do nuclear pores do?
Allow the transport of mRNA and ribosomes out of the nucleus.
What does the nuclear envelope do?
Separates contents of nucleus from the cytoplasm.
What does the nucleolus do?
Produces rRNA, tRNA and ribosomes.
What does chromatin do?
Condenses before cell division to form chromosomes.
What do the rough endoplasmic reticulum do? (2)
- Packages and stores proteins.
* Produces transport vesicles which merge to form the Golgi body.
What does the smooth endoplasmic reticulum do?
Produce, package and transport steroids and lipids.
What does the Golgi body/apparatus do? (3)
- Packages proteins for secretion from the cell.
- Modifies proteins (e.g adding carbohydrate chains to form glycoproteins)
- Produces lysosomes and digestive enzymes (tertiary structure)
What is the function of lysosomes?
- Contain powerful digestive enzymes to break down worn out organelles or cells.
- Phagocytes use them to digest engulfed bacteria.
What are centrioles?
Form the spindle during cell division.
What does mitochondria do?
ATP synthesis by aerobic respiration.
Chloroplasts’ function?
Contain photosynthetic pigments to trap light energy for photosynthesis.
What does the vacuole do?
Contains cell sap and stored solutes such as glucose.
It swells due to osmosis for turgidity.
What do ribosomes do?
For protein synthesis.
The primary protein structure is formed at the ribosome.
What does the plasmodesmata do? (2)
- Connects cells via cytoplasm filled canals which pass through cell walls.
- Allows transport via the symplastic pathway.
What does the cell wall do? (3)
- Has mechanical strength due to high tensile strength of cellulose microfibrils.
- Transports solutes via apoplectic pathway.
- Cell to cell communication via the plasmodesmata.
Name similarities between mitochondria and chloroplasts. (5)
- Double membranes.
- Highly folded inner membranes
- Circle of DNA for self-replication
- Have ribosomes
- Produce ATP
Name differences between mitochondria and chloroplasts. (3)
- Mitochondria have cristae but chloroplasts have thylakoid membranes.
- Chloroplasts contain photosynthetic pigments to absorb light and mitochondria do not.
- Mitochondria have an inner matrix but chloroplasts have a stroma.
Describe prokaryotic cells.
- Bacteria do not have membrane bound organelles like eukaryotic cells do.
- Contain no nucleus, rough endoplasmic reticulum, Golgi apparatus, mitochondria or chloroplasts.
What is a cell wall made from in a prokaryotic cell vs a eukaryotic cell?
P- Peptidoglycan
E-Cellulose
Describe viruses as they do not fit the cell theory. (4)
No: •Cell membrane •Cytoplasm •Organelles •Chromosomes
Describe the structure of a virus. (2)
- Can only reproduce with help of a host cell.
* Protein coat surrounding DNA, RNA or a few genes.
Describe atoms to systems.
Atoms—>molecules—>cells—>tissues—>organs—>systems
What are the 3 types of epithelial cells and where are they found?
- Cuboidal epithelium- in kidney tubules and intestines
- Ciliated columnar epithelium- in oviducts, trachea & bronchi.
- Squamous epithelium- Walls of alveoli
