5 Cell structure and microscopes

Question 1

What are specialised cells organised into?

Answer 1

tissues, organs, organ systems

Question 2

What are the structural features of a nucleus?

Answer 2

• surrounded by nuclear envelope which has nuclear pores
• contains chromosomes, consisting of protein-bound, linear DNA, and one/ more nucleoli

Question 3

What are the structural features of the cell surface membrane?

Answer 3

very thin phospholipid bilayer with proteins, glycoproteins, glycolipids, and cholesterol

Question 4

What is the function of the nucleus?

Answer 4

controls gene expression and mediates replication of DNA during cell cycle

Question 5

What is the function of the cell surface membrane?

Answer 5

partially permeable so controls exchange between cell and environment

Question 6

What is the name of the cell organelle that builds proteins?

Answer 6

rough endoplasmic reticulum

Question 7

What is the name of the cell organelle that releases lysozyme?

Answer 7

lysosome

Question 8

What are the structural features of a mitochondria?

Answer 8

• long rod-shaped
• smooth outer membrane
• has inner membrane highly folded into cristae

Question 9

What is the function of the mitochondria?

Answer 9

• carries out aerobic respiration, which takes place in matrix and on cristae
• synthesises ATP

Question 10

What is a structural feature of ribosomes and their function?

Answer 10

• tiny granules
• site of protein synthesis
• 80s in eukaryotic cells, 70s in prokaryotic

Question 11

What is a structural feature of the rough endoplasmic reticulum (RER) and its function?

Answer 11

• an extended system of membrane sacs
• encrusted with ribosomes
• synthesises proteins

Question 12

What is a structural feature of the smooth endoplasmic reticulum (SER) and its functions?

Answer 12

• similar to RER, but no ribosomes
• synthesises lipids and hormones
• synthesises, stores, and transports carbohydrates

Answer 13

• stacks of flattened membranes
• modifies proteins
• makes lysosomes
• collects, processes, and sorts molecules that are then transported in Golgi vesicles to other parts of the cell/ secreted out

Question 14

What is a lysosome and its function?

Answer 14

a Golgi vesicle that releases lysozyme

Question 15

What is the name of the cell organelle that makes lipids, steroids, and some hormones?

Answer 15

smooth endoplasmic reticulum

Question 16

Which organelles are involved with protein synthesis?

Answer 16

nucleus, rough endoplasmic reticulum (RER), ribosomes, Golgi apparatus and vesicles

Question 17

What is the name of the cell organelle that carries out photosynthesis?

Answer 17

chloroplast

Question 18

What are the 2 types of cell that form all life?

Answer 18

eukaryotic and prokaryotic

Question 19

What is a structural feature of the permanent vacuole and its function?

Answer 19

contains sap and supports the plant

Question 20

What is a structural feature of the cell wall and its function?

Answer 20

• composed of cellulose in plants, chitin in fungi, and cellulose and/or glycoproteins in algae
• provides strength whilst remaining permeable

Question 21

What is a structural feature of chloroplasts and its function?

Answer 21

• disc-like thylakoid membranes arranged in stacks called grana
• internal fluid= stroma
• light-dependent reactions of photosynthesis take place on thylakoid membranes, light independent reactions in stroma

Question 22

Which 3 organelles do plant cells have that are not present in animal cells?

Answer 22

permanent vacuole, cell wall, chloroplasts

Question 23

What type of cells are animal, fungal, and plant cells?

Answer 23

eukaryotic

Question 24

What type of cells are bacteria?

Answer 24

prokaryotic

Question 25

What features do prokaryotic cells possess that eukaryotic cells don't have?

Answer 25

- cytoplasm lacks membrane-bound organelles - smaller ribosomes (70S) - no nucleus, instead circular loop DNA that's free in cytoplasm and has no associated proteins - a cell wall that contains murein, a glycoprotein - capsule surrounding cell

Question 26

What is the cell wall in prokaryotic cells made up of?

Answer 26

murein, a glycoprotein

Question 27

What do prokaryotic cells have one or more of?

Answer 27

one or more plasmids/ flagella

Question 28

What are the 3 components of a virus particle?

Answer 28

genetic material, capsid, attachment protein

Question 29

How can you calculate the magnification of an object?

Answer 29

magnification= image size/ actual size of object

Question 30

What are the principles of light microscopy?

Answer 30

- uses light as source of radiation - light can be seen that passes through/ reflects from surface of specimen

Question 31

What are the principles of transmission electron microscopes (TEM)?

Answer 31

- uses electrons as source of radiation - electrons that pass through specimen are detected

Question 32

What are the principles of scanning electron microscopes (SEM)?

Answer 32

- uses electrons as source of radiation - electrons that are reflected from surface on specimen detected

Question 33

What is an advantage and disadvantage of the light microscope?

Answer 33

living and non-living specimens can be observed, but magnification and resolution is weaker

Question 34

What is a disadvantage of the TEM and SEM?

Answer 34

only dead/ non-living specimens can be used

Question 35

What is an advantage of the TEM?

Answer 35

higher resolution

Question 36

Which stain can be used to colour starch granules in plant cells?

Answer 36

iodine dissolved in potassium iodide

Question 37

Why is cell fractionation and ultracentrifugation used?

Answer 37

to separate cell components by mass for analysis

Question 38

Describe what takes place in cell fractionation and ultracentrifugation

Answer 38

1. tissue cut up and kept in cold, isotonic, and buffered solution 2. tissue further broken up in homogeniser 3. spun in ultracentrifuge 4. 3 types of supernatant and pallet formed (spun at low, medium, and high speed)