Cells Flashcards
What is the function of the Ribosomes
Site of Protein synthesis;
What is the function of the Nucleus
Contains genetic material / DNA;
Controls cell activity;
What is the function of the Mitochondria
Site of aerobic respiration;
ATP production by aerobic respiration
What is the function of the Smooth Endoplasmic Reticulum
Site of lipid synthesis;
What is the function of the Rough Endoplasmic reticulum
Encrusted in Ribosomes;
Site of protein synthesis;
Transports and stores protein within the cell
What is the function of Golgi Apparatus
Modifies/packages/sorts proteins;
Produces vesicles;
What is the function of Lysosomes
Contains digestive (hydrolytic) enzymes;
Digests worn out organelles/autolysis;
What is the function of Cell surface membrane
Made of a Phospholipid Bi-layer;
Controls what enters the cell/ is selectively permeable;
Can be folded to increase Surface Area;
What is the function of centrioles
Form spindle fibers to pull apart the chromosomes/ chromatids.
What is the function of nucleolus
To synthesise ribosomal RNA (rRNA) for the production of ribosomes
Define eukaryotic cell
-A eukaryotic cell has membrane bound organelles
-A eukaryotic cell has a nucleus containing linear DNA/chromatin
How does mRNA leave the nucleus to the cytoplasm?
Leaves through the nuclear pores in the nucleus envelope
What is chromatin?
(Uncondensed) DNA within the nucleus coiled around the histones.
This super-condenses to form chromosomes during cell division
What are microvilli?
Microvilli are finger like projections of cell membrane that increase the surface area to speed up absorptions.
(Found on epithelial cells in small intestine)
What organelles have a double plasma membrane?
Nucleus, Mitochondrion and the Chloroplast
What is the function of a Chloroplast?(2marks)
Contain Thylakoid stacked into Granum
-Absorbs/uses light
-for photosynthesis
-produces carbohydrates/sugar/lipids/protein
Apart from the nucleus, what other organelles contain DNA?
Chloroplast and Mitochondria
What is the function of Cell Wall
Provides rigid shape / structure;
Stops osmotic lysis;
What is the function of Plasmid
Circular DNA;
Contains antibiotic resistance genes;
What is the function of the plasmodesmata in the cell wall?
Gaps in the cell walls that connect cell cytoplasm’s together to allow movement of water soluble molecules.
What is a capsid?
Its a protein coat that surrounds a virus
Describe how you could use cell fractionation to isolate chloroplasts from leaf tissue (3)
- Break open the cells in a blender/ homogeniser and filter to remove cellular debris;
- Place in an ice cold, isotonic, buffered solution;
- Use differential centrifugation;
- Chloroplasts are in the second pellet;
Scientists isolated mitochondria from liver cells. They broke the cells open in an ice-cold, buffered isotonic solution. Explain why the solution was:
a) Isotonic
b) Ice cold
c) buffered
- Prevents osmosis
so no osmotic lysis of organelles/named organelle (e.g. mitochondria); - Reduce/prevent enzyme activity so organelles are not digested;
- Maintain a constant pH so proteins are not denatured;
Name the reaction that forms ATP
Aerobic respiration
Name the reaction that breaks down ATP
Phosphorylation
What are Cell Surface Membranes made up of?
Made up of phospholipids, specific transport proteins, and carbohydrates arranged into a fluid mosaic model
What is the folding of the inner membrane in mitochondria called and what is its function?
Cristae, increases surface area for the attachment of ATP synthase enzymes (enzymes that make ATP)
Name the process by which proteins are secreted from the cell (leave the cell)
Exocytosis
Explain why electron microscopes can see smaller organelles than light microscopes
Electron microscopes have a higher resolution
Uses electrons which have a smaller wavelength
Describe how TEM works and what are the disadvantages
How it works:
- Electrons pass through / enter (very thin) specimen;
- Denser parts absorb more electrons;
- (So) denser parts appear darker;
- Electrons have short wavelength so give high resolution;
Disadvantages:
- Cannot look at living material / Must be in a vacuum;
- Specimen must be (very) thin;
- Artefacts present;
- Complex staining method / complex / long preparation time;
Give one advantage of using a TEM rather than a SEM
Higher resolution / higher magnification / higher detail
OR
Allows internal details / structures within cells to be seen
Give one advantage of using a SEM rather than a TEM
Thin sections do not need to be prepared / shows surface of specimen / can have 3D images
Explain why mitochondria can appear in different shapes (2 marks)
- Idea of sections or cuts
- Idea of mitochondria orientated differently or in different positions (viewed from a different angle) / description of 3D structure of mitochondria, e.g sausage-shaped
