Prokaryotic And Eukaryotic Cells Flashcards
How does the size differ between prokaryotic cell and eukaryotic cells?
- Prokaryotic cells are small about 0.1 - 10 micrometers
- Eukaryotic cells are larger about 10 -100 micrometers
What is the complexity like of a prokaryote?
They are simple and make up unicellular organisms like bacteria
What is the complexity like of a eukaryote?
They are larger more complex cells which make up multicellular organisms like animal, plant and fungi
Where is DNA found in prokaryotic cells?
It is free floating in the cytoplasm in an area called the nucleoid
What is the structure of the genetic material in prokaryotic cells?
DNA is a double helix
DNA has a CIRCULAR structure
DNA is NOT associated with proteins
What is the extra DNA in prokaryotic cells called?
Plasmids (extra loops found in the cytoplasm)
What don’t prokaryotic have any of?
Membrane bound Organelles
What size are the ribosomes like in prokaryotic cells?
70 S
What is the cell wall made up of of in prokaryotic cells?
Murein (glycoprotein - protein attached with a carbohydrate)
What is found on the outer layer of some prokaryotic cells?
Slime capsule (protects against the attack of cells in immune system)
Do prokaryotic cells have a cell membrane?
YES
Do eukaryotic cells have a cell membrane?
YES
What do some prokaryotic cells have to help them move ?
Flagella
Where is DNA found in a eukaryotic cell?
In the NUCLEUS (membrane bound)
What is the structure of DNA in a eukaryotic cell?
DNA is a double helix
DNA is associated with histone proteins
DNA has a LINEAR structure
NO PLASMIDS
What are most organelles surrounded by in eukaryotic cells?
Phospholipid bilayer (membrane bound organelles)
What is the size of ribosomes in eukaryotic cells?
80S
What is the only organelle which isn’t membrane bound?
Ribosomes
What is the cell made out of in eukaryotic cells (plants/fungi)?
Plants = Cellulose
Fungi = Chitin
What type of channels do cellulose cell walls sometimes have?
Plasmodesmata ( channels for exchanging substances)
Do eukaryotic cells have a protective outer layer?
No slime capsule but do have a Vacuole to aid rigidity
Do eukaryotic cells have a cytoplasm?
Yes
Do eukaryotic cells have a cell membrane?
Yes
Can eukaryotic cells have a flagellum?
Yes (only sperm cells)
How do prokaryotic cells divide?
Binary fission
What is the function of the nucleus?
- Controls the cells activities (by controlling transcription of DNA and protein synthesis)
- Contains the organism’s genetic material
Describe the structure of the nucleus?
The nucleus in contained with a nuclear envelope which contains nuclear pores.
Inside the nucleus there is a nucleolus and chromatin
What is the purpose of the nuclear envelope?
The double membrane around the nucleus and connects to the endoplasmic reticulum whilst controlling the entry and exit of materials
What is the purpose of nuclear pores?
Allows the movement of large molecules (mRNA) out of the nucleus
What is the function of the nucleolus?
Manufactures and resembles ribosomes from rRNA
What is the purpose of chromatin?
DNA exists as this in the nucleus and condenses into chromosomes during cell division
What is the function of Rough endoplasmic reticulum (RER)?
Folds and processes proteins made at ribosomes before budding off into vesicles for transportation
Why is the endoplasmic reticulum ROUGH?
It has ribosomes on it
What is the function of smooth endoplasmic reticulum (SER)?
Synthesise and transports lipids and carbohydrates
What is cisternae?
The membranes form a network of tubules and flattened air sacks (endoplasmic reticulum and Golgi apparatus)
What is the function of chloroplasts?
Contain chlorophyll for absorption of light for photosynthesis (converts light to chemical energy by phosphorylation to produce ATP)
What is the stroma in chloroplasts ?
Stroma is a fluid filled space filling the rest of the chloroplast and it’s where the second stage of photosynthesis occurs (synthesis of sugars)
What is the grana in a chloroplasts?
They are stacks of disc like structures called thylakoids
What is a thylakoid?
Contains photosynthetic pigment (chlorophyll) so absorbs sunlight for photosynthesis (provide a large surface area)
What is lamellea?
Connective tissue joining adjacent grana
Where are the energy stores in chloroplasts?
Starch grains in the stroma store glucose made from photosynthesis
What are the internal structures of a chloroplast?
Have a double membrane, grana, thylakoids, lamellae and stroma
What are the structures of a mitochondrion?
Outer membrane, Inter-membrane space, inner membrane, cristae, matrix, 70s ribosomes and circular DNA
What type of ribosomes do mitochondria have?
70S
What is the function of mitochondria?
Site of aerobic respiration which produces ATP (immediate energy source)
What is the purpose of cristae?
The inner membrane is folded to form this and aerobic respiration occurs here
What is the purpose of the matrix?
Contain ribosomes, circular DNA and all enzymes required for respiration
What is the function of the Golgi Apparatus?
It processes, modifies and packages new lipids and proteins for transportation
What does the Golgi apparatus do?
Modifies and packages proteins before budding off into Golgi vesicles and travelling to their destination
What makes lysosomes?
The Golgi apparatus
How are lysosomes formed?
Form when vesicles that bud off Golgi apparatus contain hydrolytic enzymes
What is the function of lysosomes?
- Hydrolyse material taken up by phagocytic cells
- Digest old organelles
- Breaks down dead cells
What is the function of ribosomes?
Site of protein synthesis
Where are ribosomes found?
Cytoplasm or rough endoplasmic reticulum
What are ribosomes made from?
rRNA and protein
Small sub-unit and large sub-unit
What are the two sizes of ribosomes?
70S and 80S
What is the function of a vacuole?
- Helps maintain pressure in the cell and support plant by making cells turgid/rigid
- Store useful substances (water, sugar and amino acids)
- Isolate unwanted/harmful products in the cell
What is a vacuole?
A tonoplast membrane filled with fluid
What is the function of a cell membrane?
Regulates the movement of substances into and out of the cell
What is the function of the cell wall?
Provides cells with strength to prevent it bursting due to osmotic gain/loss of water
What is the function of centrioles?
- Support the cells shape
- Form spindles during cell division
How do organelles in a cell work together to produce and transport a protein?
- mRNA copies gene sequence
- mRNA leaves the nucleus via nuclear pores and attaches to the rough endoplasmic reticulum
- mRNA attaches to the ribosome which makes new proteins using the code from the RNA, the proteins anew then packaged and transported in vesicles
- Vesicles bud off the endoplasmic reticulum and travel towards the Golgi apparatus
- Vesicle fuse to the Golgi apparatus
- Golgi apparatus packages and modifies the proteins ready for release
- Golgi vesicles bud off Golgi apparatus and are labelled and transported to their destination
- Golgi vesicles fuse to plasma cell membrane
- Exocytosis as protein is released outside the cell
What theory suggest eukaryotic cells evolved from prokaryotic cells?
Endosymbiotic theory
How does the endosymbiotic theory suggest how mitochondrion and chloroplasts evolve?
Evolved from engulfed prokaryotes (an aerobic prokaryote and a photosynthetic prokaryote) that once lived as independent organisms but evolved inside prokaryotic cells to become chloroplasts and mitochondria.
Why did mitochondria evolve?
They provided the prokaryotic cells with a survival advantage - by providing ATP
Why did chloroplast evolve?
Provided a competitive advantage for the cell - provided an alternative energy source (carbohydrate)
What is the evidence to prove the endosymbiotic theory?
- Circular DNA found in both mitochondria and chloroplasts
- 70S ribosomes found in both
- Both surrounded by a double plasma membrane
- Both divide by binary fission/similar
What is a tissue?
A group of similar cells organised in a structural unit working together to perform a specific function
What is an organ?
More than one tissue working together to perform a specific function
What is an organ system ?
Multiple different organs working together to perform a specific function
What is an example of an organ?
Arterioles
What does ACELLULAR mean?
It’s not a cell (non-living)
Why are viruses acellular?
They don’t satisfy the living criteria (MRS GREN)
What does MRS GREN stand for?
Movement
Respiration
Sensitive
Growth
Reproduction
Excretion
Nutrition
What type of genetic material do viruses contain?
DNA or RNA
Where is the genetic material stored in a virus?
Inside the Capsid
What do viruses have on their cell surface membrane?
Attachment proteins which provide the ability to attach to a host cell
What are two features of viruses which are sometimes present (not always)?
Lipid envelope
Reverse transcriptase (enzyme)
Describe viral replication?
- Virus attaches to host cell (with its attachment proteins which bind to the protein receptors on the host cell surface membrane
- The virus injects it’s genetic material into the host cell and this is used to synthesise viral proteins
- New viral particles are assembled
- New viruses burst out of and damage/destroy the host cell