Summary
Summary WJEC (Wales) Unit 1 Biology Prokaryotic cells notes
- Institution
- WJEC
Notes are written for the WJEC unit 1 biology exam titles included: structure of prokaryotic cell viruses types of muscles and epithelial cells
[Show more]
Seller
Follow
Content preview
Prokaryotic cellCharacteristics:
Unicellular
Lack all membrane bound organelles
Smaller size
Organelles:
1. Nucleoid (DNA)
- X nucleus, free in cytoplasm
- X associated to anything
- circular, non-linear
2. Plasmids
- additional circular loops of DNA in some prokaryotes
- contain important genes, e.g. those that confer antibiotic resistance
- can move between cells/species (conjugation)
∴transmission of antibiotic resistance in bacteria
Functions:
Exchange DNA between bacterial cells
Useful for genetic engineering
Vectors to carry specific DNA sequence in recombinant DNA technology
3. Ribosomes
- smaller & free in cytoplasm
- 70s type
4. Peptidoglycan (murein) cell wall
- peptidoglycan = glycoprotein
- Contains varying amount of lipopolysaccharides & lipoproteins
Functions:
Complex, semi-rigid structure gives cell shape, prevents rupture, anchorage pt for flagella
Peptidoglycan forms basis of diagnostic gram stain
Contributes to virulence
5. Mesosomes
, - some present
- in-folded areas of membrane produce ATP
- contains respiratory enzymes
Function:
Contain all membrane-bound proteins required for respiration & photosynthesis
6. Cytoplasm
- contains all enzymes for metabolic rxns
7. Cell membrane
- made from phospholipids & proteins
- less rigid than eukaryotes
8. Capsule
- some present
- Glycocalyx -> viscous, gelatinous layer outside cell wall, made of polysaccharide and/or polypeptide
- firmly attached = capsule, loosely attached = slime layer
Function:
Contribute to virulence in pathogenic species, protect bacteria from immune system of host
Glycocalyx enables attachment to substrates
∴ stick cells tgt
Food reserve
Protection against desiccation & chemicals, phagocytosis
9. Flagella
- some hv
- for locomotion
- rigid rotating helical-shaped tail for propulsion
- arrangement: single polar, one/more at cell ends, distributed over entire cell
10. Fimbriae
Hair-like structures, form fringe around some bacteria
Shorter, straighter, thinner
For attachment to other cells
11. Pili
- similar to fimbriae, longer, less numerous
- involved in bacterial conjugation & as phage receptors
12. Photosynthetic lamellae
- highly folded extensions of cell membrane
- photosynthetic pigments are embedded
Endosymbiosis (theory by Biologist Lynn Margulis)
States mitochondria & chloroplasts were once free-living prokaryotic organisms
The benefits of buying summaries with Stuvia:
Guaranteed quality through customer reviews
Stuvia customers have reviewed more than 700,000 summaries. This how you know that you are buying the best documents.
Quick and easy check-out
You can quickly pay through credit card for the summaries. There is no membership needed.
Focus on what matters
Your fellow students write the study notes themselves, which is why the documents are always reliable and up-to-date. This ensures you quickly get to the core!
Frequently asked questions
What do I get when I buy this document?
You get a PDF, available immediately after your purchase. The purchased document is accessible anytime, anywhere and indefinitely through your profile.
Satisfaction guarantee: how does it work?
Our satisfaction guarantee ensures that you always find a study document that suits you well. You fill out a form, and our customer service team takes care of the rest.
Who am I buying these notes from?
Stuvia is a marketplace, so you are not buying this document from us, but from seller aliesefan. Stuvia facilitates payment to the seller.
Will I be stuck with a subscription?
No, you only buy these notes for £7.49. You're not tied to anything after your purchase.
Can Stuvia be trusted?
4.6 stars on Google & Trustpilot (+1000 reviews)
68175 documents were sold in the last 30 days
Founded in 2010, the go-to place to buy revision notes and other study material for 15 years now