Topic 2A: Cells Exam Questions Flashcards
Describe the structure and function of the nucleus. [4]
Structure:
1. Nuclear envelope and pores;
2. Chromosomes/chromatin OR DNA with histones;
3. Nucleolus/nucleoli;
Function:
4. (Holds/stores) DNA/genetic information which codes for polypeptide production OR (DNA is) code for polypeptides;
5. DNA replication (occurs);
6. Production of mRNA/tRNA OR Transcription (occurs);
7. (Nucleoli) produce rRNA/ribosomes.
Eukaryotic cells produce and release proteins.
Outline the role of organelles in the production, transport and release of proteins from eukaryotic cells.
Do not include details of transcription and translation in your answer. [4]
- DNA in nucleus is code (for protein);
- Ribosomes/rough endoplasmic reticulum produce (protein);
- Mitochondria produce ATP (for protein synthesis);
- Golgi apparatus modify;
- Vesicles transport;
- (Vesicles) fuse with cell(-surface) membrane.
Describe the three functions of the Golgi apparatus in a eukaryotic cell. [3]
- Modify/package/transport proteins;
- Modify/package/transport lipids;
- Forms vesicles/lysosomes.
Compare and contrast the structure of mitochondria and chloroplasts. [4]
Similarities:
1. Double membrane;
2. Both contain (circular) DNA;
3. Both contain ribosomes;
Differences:
4. Thylakoids/grana vs cristae;
5. Stroma vs matrix;
6. Pigment vs no pigment;
7. Starch grains vs no starch grains.
A lack of certain inorganic ions can cause chloroplasts to contain less thylakoids membrane than normal.
Suggest why this deficiency will cause plants to have a reduced growth rate. [3]
- Smaller surface area / less chlorophyll;
- (So) reduced light absorption;
- (So) slower rate of photosynthesis.
State in which process ribosomes are important. [1]
- Protein synthesis
State the organelle that is being referred to in each of the following descriptions:
a. It possesses structures called cristae.
b. It contains chromatin.
c. It synthesises glycoproteins.
d. It digests worn out organelles.
a. Mitochondria
b. Nucleus
c. Golgi apparatus
d. Lysosome
Give one feature found in all prokaryotic cells that is not found in eukaryotic cells. [1]
- Circular/loop of DNA in cytoplasm / DNA free in cytoplasm / DNA not associated with proteins/histones / Murein in cell wall / smaller ribosomes in cytoplasm / only have smaller ribosomes / no membrane-bound organelles
Give two structures found in all prokaryotic cells and in all eukaryotic cells. [2]
- Cell(-surface) membrane;
- Ribosomes;
- Cytoplasm;
- DNA.
Contrast the structure of a bacterial cell and the structure of a human cell. [5]
- Bacterial cell is much smaller than a human cell;
- Bacterial cell has a cell wall but a human cell does not;
- Bacterial cell lacks a nucleus but human cell has a nucleus;
- Bacterial cell lacks membrane-bound organelles but human cell has membrane-bound organelles;
- Bacterial ribosomes smaller than human ribosomes (in cytoplasm);
- Bacterial DNA is circular but human DNA is linear;
- Bacterial DNA is not bound to protein whereas human DNA is bound to histones/proteins.
DNA and RNA can be found in bacteria.
Give two ways in which the nucleotides in DNA are different from the nucleotides in RNA. [2]
- DNA contains thymine and RNA contains uracil;
- DNA contains deoxyribose and RNA contains ribose.
Describe how lactose is formed and where in the cell it would be attached to a polypeptide to form a glycoproteins. [4]
- Glucose and galactose;
- Joined by condensation (reaction);
- Joined by glycosidic bond;
- Added to polypeptide in Golgi (apparatus).
Name the process by which prokaryotic cells divide. [1]
- Binary fission
Give the function of a mitochondrion. [1]
- The site of aerobic respiration (reactions)
OR
ATP is made.
Milk is produced and secreted by gland cells. These gland cells have adaptations that include many mitochondria and many Golgi vesicles. The milk contains a high concentration of protein.
Explain the role of these cell adaptations in the production and secretion of milk. [2]
- (Many mitochondria) release energy / ATP for movement of vesicles/synthesis of protein/active transport;
- (Many Golgi) vesicles transport protein/glycoprotein/milk to cell membrane/out of cell.
What are the differences between an optical microscope and an electron microscope. [5]
- Uses light vs uses electrons;
- Lower resolution vs higher resolution;
- Only larger organelles can be observed and organelles are seen in less detail vs smaller organelles can be observed and organelles can be seen in more detail;
- Can be used on living or dead specimens vs specimen will be dead;
- Can show colour vs does not show colour;
- Less time-consuming/complex preparation vs more time-consuming/complex preparation;
- Focuses using glass lenses vs focuses using magnets.