Cell Structure Flashcards
Give 3 benefits of using optical microscopes
- Relatively cheap
- Easy to use
- Portable
State 2 benefits of laser scanning microscopes
- Produce high resolution/high contrast images
Do electron microscopes have good resolutions?
Yes
Which type of electron microscope has a larger magnification?
Transmission; x2 million
Scanning; x15 –> x200,000
Give one similarity between the images produced by transmission and scanning electron microscopes
- Both produce black and white images
Which type of microscope produces a 3D image?
Scanning electron microscopes
Which type of microscope requires the specimen to be chemically fixed before viewing?
Transmission electron microscopes
What is the function of the nuclear envelope?
Separates the nucleus from the rest of the cell
What does the nucleolus contain?
RNA
What is made in the nucleolus?
Ribosomes
Name the chemical which makes up genetic material
Chromatin
Where is chromatin found in a cell?
Nucleus
What is the main function of the nucleus?
To control the activities of the cell
Describe the structure of the rough endoplasmic reticulum
- System of membranes, covered in ribosomes
What is the role of rough endoplasmic reticulum?
To process and packaging proteins
Why is the rough endoplasmic reticulum coated in ribosomes?
To assemble amino acids into protein
Why does the smooth endoplasmic reticulum contain enzymes?
To catalyse reactions
Give some examples of reactions that take place in the smooth endoplasmic reticulum
- Synthesis of steroid hormones
- Synthesis of cholesterol
- Synthesis of lipids
Describe the structure of the Golgi apparatus
A stack of membrane bound flattened sacs
What is the role of the Golgi apparatus?
Protein modification
What is the function of the mitochondria?
- Site of ATP production
- Aerobic respiration
How are mitochondria structured?
Fluid-filled matrix
What reaction occurs in chloroplasts?
Photosynthesis
How are chloroplasts structured?
- Surrounded by double membrane
- Inner membrane consists of thylakoid
What role does a vacuole perform?
Helps support plant cells, filled with water and solutes
What is the purpose of lysosomes?
- To digest large molecules and engulf foreign matter
- Uses powerful hydrolytic enzymes
Which 3 organelles aren’t membrane-bound?
- Ribosomes
- Cytoskeleton
- Cell Wall
What is the role of ribosomes?
To synthesise proteins
What is the cytoskeleton?
A network of protein structures which support the cell and allow for movement within the cell
How do cytoskeletal motor proteins work?
- They move things along microtubules
- Energy from hydrolysis of ATP
What is a cell wall made from?
Bundles of cellulose fibres
What is the function of the cell wall?
- Prevent cells from bursting
- Provide rigid structure to cell
Describe the first step in making proteins
- Gene, with instructions for creating that specific protein, are transcribed onto mRNA
What happens after a gene is transcribed onto mRNA, when making proteins?
mRNA is copied and passes through pores in nuclear envelope
During the process of making proteins, what occurs after mRNA copies leave the nuclear envelope?
Instructions are translated and protein molecule is assembled at ribosomes
How do protein molecules get to the Golgi apparatus from the rough endoplasmic reticulum?
- Molecules pass along cisternae
- They enter vesicles and pass via microtubules and motor proteins to the Golgi apparatus
How do vesicles release or extract protein molecules from the Golgi Apparatus?
By fusing or being pinched off the Golgi
How are protein molecules released from vesicles to outside the cell?
Vesicles fuse with the plasma membrane and protein is released
Name three sub-cellular structures that are common in eukaryotes and prokaryotes
- Ribosomes
- Cytoplasm
- Plasma membrane
Do prokaryotes contain both DNA and RNA?
Yes
Which type of cell is much smaller?
Prokaryotes or Eukaryotes
Prokaryotes
Give one difference between the cytoskeleton of eukaryotes and prokaryotes
Prokaryotes have less developed cytoskeletons
Do prokaryotes have a nucleus?
NO - GCSE BIOLOGY
What are prokaryotic cell’s walls made of?
Peptidoglycan
What type of organelles do prokaryotes not have?
Membrane-bound organelles
State 3 features of prokaryotic cells
- Naked, free-floating plasmids
- Flagella
- Smaller ribosomes
- Protective waxy capsule
