2.2 Types of Cells + Parts of the Cells Flashcards
What are Prokaryotic Cells?
- Prokaryotic cells are smaller, simpler, and less specialised, essentially containing no membrane-bound structures called organelles, inside them.
What do Prokaryotic Cells contain?
- A prokaryotic cell is typically described as a rod-shaped single bacterium which includes;
○ The cytoplasm consists of the fluid cytosol with suspended internal structures.
○ Ribosomes: non membrane-bound organelles that are at the site for protein synthesis.
○ A cell membrane (or plasma membrane) which is surrounded by a cell wall.
○ A single circular chromosome made up of DNA.
○ Small circular rings of DNA called plasmids are often present in the cytoplasm.
What are Eukaryotic Cells?
- Eukaryotic cells tend to be larger and more complex; they are predominantly found in multicellular organisms but not exclusively.
What do Eukaryotic Cells contain?
- Contain many membrane-bound structures called organelles which have specific structures that suit their particular function in the cell including:
○ Nucleus, Mitochondria, Golgi Body (apparatus) and Chloroplasts.
What are the main features of a Prokaryotic Cell?
Size = Small (1-10µm)
DNA Type = Circular DNA
Cell Type = Unicellular
Organisation = Little cell organisation (rod-shaped single bacterium)
Chromosome Shape = One circular chromosome
Location of Chromosome(s) = In Cytoplasm
Nucleus or Not =No Nucleus
Membrane-bound organelles = No Membrane bound organelles
Ribosomes = Present
Cell Division = Binary Fission
Cell Wall = Made of Peptidoglycan
Cell Membrane and Cytoplasm = Present
What are the main features of Eukaryotic Cells?
Size = Large (10–100µm)
DNA Type = Linear DNA
Cell Type = Multicellular
Organisation = High level of internal organisation
Chromosome Shape = Two or more linear chromosomes
Location of Chromosome(s) = In Nucleus
Nucleus or Not = Contains a Nucleus
Membrane-bound organelles = Contains many membrane bound organelles
Ribosomes = Present
Cell Division = Mitotic Division
Cell Wall = Made of Cellulose (if present)
Cell Membrane and Cytoplasm = Present
What is a Nucleus?
- Has a double membrane boundary called the nuclear envelope (contains nuclear pores)
- Contains chromosomes (DNA and proteins) - however only visible during cell division
- All other times the DNA exists as chromatin - long thin strands with no distinct shape
- Contains a nucleolus which is composed of DNA and protein, and the site of ribosomal RNA (rRNA) synthesis
- The function of the nucleus is to control cell activities and to pass on hereditary information to the next generation
Stores and transmits information
What is the Mitochondria?
- Consists of a smooth outer membrane and an extensively folded inner membrane that create a structure called cristae
- Latter stages of aerobic respiration are carried out here to produce large amounts of energy from the breakdown of organic molecules
- The highly folded inner membrane is studded with enzymes that are necessary for respiration to occur
What is a Chloroplast?
- Site of photosynthesis
- Double membrane bond
- Internally there are flattened sacks called thylakoids arranged in stacks called granum
- The fluid surrounding the granum is called stroma
- Thylakoids store the pigment chlorophyll which captures light energy for photosynthesis
The first stage of photosynthesis occurs in the grana. The final stage, which needs enzymes, occurs in the stroma.
What is the word equation for Photosynthesis
Carbon Dioxide + Water (in the presence of light)»_space;»»»»»> Glucose + Oxygen
What is the equation for Photosynthesis?
6CO2 + 6H2O) (chlorophyll, in the presence of light)»_space;»»> C6H12O6 + 6O2
What is a Vacuole?
- Membrane bound fluid-filled space
- It is a relatively large structure in plants (centrally located) and very small structure in animal cells
- The fluid contains solutes which include:
○ Salts (ions)
○ Simple sugars ○ Amino acids
What is the function of a Vacuole?
○ Storage (e.g. Water, oil)
○ Maintain osmotic balance (water and salt balance)
○ Cell shape (via cell turgidity)
- Some unicellular animals living in fresh water have special ‘contractile’ vacuoles that can pump water out
- Animals cells can contain ‘food vacuoles’ that store food particles
What is the Rough Endoplasmic Reticulum?
- Is a system of internal folded membranes that are continuous with the outer membrane of the nucleus
- Two types:
○ Rough ER:- Ribosomes attached
- Main function is the modification and transport of proteins throughout the cell
What is the Smooth Endoplasmic Reticulum?
- No ribosomes attaches
- Main function is lipid synthesis and carbohydrate metabolism
