Cell Structure

Question 0

Organelle

Answer 0

-A structure of a cell with a specialised function.

Question 1

Seven life processes (7)

Answer 1

• Movement
• Respiration
• Sensitivity
• Nutrition
• Excretion
• Reproduction
• Growth

Question 2

Division of labour

Answer 2

-When each organelle has a specific function

Question 3

Cytoskeleton

Answer 3

-An internal framework of protein fibres that supports the shape of the cell and moves organelles within

Question 4

Microtubules (4)

Answer 4

• 25nm in diameter
• Made of a protein called tubulin
• Used to move organisms through a liquid or waft a liquid past a cell (e.g. Moving chromosomes during mitosis or moving Golgi vesicles)
• These proteins are known as microtubule motors and use ATP

Question 5

Flagella (undulipodia) and cilia

Answer 5

• Made up of a cylinder of 9 microtubule pairs with one pair in the centre
• Undulipodia are longer than cilia
• Microtubules use ATP to move
• Undulipodia exist in ones or twos on cells
• Cilia occur in large number
• Flagella are made of a spiral protein (flagellin) attached by a hook to a protein base
• Disk spins using ATP

Question 6

Vesicles and vacuoles (3)

Answer 6

• Membrane bound sacs in a cell
• Used to carry substances around the body
• The vacuole in plant cells provides cell stability by pushing against the cell wall an making it turgid

Question 7

Cell wall (3)

Answer 7

• Made of cellulose; a carbohydrate polymer made up of glucose
• Cellulose forms a sieve like network
• Supports the cell as it held rigid by the pressure from the vacuole

Question 8

Nucleus (3)

Answer 8

• Consists of genetic material and proteins
• Holds instructions for protein synthesis
• Controls what enters and leaves the cell

Question 9

Chromatin

Answer 9

-Dark patches condense into visible chromosomes during cell division

Question 10

Rough endoplasmic reticulum

Answer 10

-Transports proteins that were made on the attached ribosomes

Question 11

Smooth endoplasmic reticulum

Answer 11

-Makes lipids for use in cells (e.g. Cell membranes)

Question 12

Golgi apparatus

Answer 12

• Receives proteins from the endoplasmic reticulum’s and modifies them
• Packaged and sent off to be transported in a vesicle
• Vesicles can be secreted out the cell

Question 13

Mitochondrion (3)

Answer 13

• Where ATP is produced during aerobic respiration
• Inner membrane is tightly folded to form cristae
• Central part of mitochondrion is called the matrix

Question 14

Chloroplasts (2)

Answer 14

• Site of photosynthesis in plants cells

- Light energy is used to initiate this reaction making carbohydrate molecules from water and carbon dioxide

Question 15

Lysosomes (3)

Answer 15

• Contains powerful enzymes to break down materials
• E.g. White blood cell lysosomes break down foreign pathogens.
• Lysosomes in the head of a sperm breaks down the surrounding wall of an egg

Question 16

Ribosome

Answer 16

• Not membrane bound

- Site of protein synthesis

Question 17

The hormone production sequence (9)

Answer 17

1. mRNA copy of the instructions are made
2. mRNA leaves nucleus via a nuclear pore
3. mRNA attaches to ribosome where it is read and assembled into a protein
4. Hormone molecule is contained in a vesicle and travels to the Golgi apparatus
5. Vesicle fuses with Golgi apparatus
6. Golgi apparatus packages molecule for release
7. Packaged molecule moves towards plasma membrane
8. Vesicle fuses with plasma membrane
9. Plasma membrane opens to release molecule

Question 19

Eukaryotes (5)

Answer 19

• Cells that contain membrane bound organelles and have a true nucleus
• Genetic material held in a nucleus
• 15~25 micrometres in diameter
• Ribosomes are 22nm in diameter
• Cell wall is sometimes present

Question 19

Prokaryotes and disease (3)

Answer 19

• Some prokaryotic cells are well known for causing disease and a few of those are resistant to antibiotics as well
• The resistance is coded on the plasmid so it can be passed onto other bacterial cells
• Researchers are looking for antibiotics that slow down the grown of bacterial cells while not harming the eukaryotic cells

Question 20

Prokaryotic cells (10)

Answer 20

• Don’t contain membrane bound organelles
• Have a plasma membrane
• Have a cell wall made of peptidoglycan
• Have small ribosomes 10nm in diameter
• DNA is formed in a single loop called a circular chromosome
• Can have plasmids
• Has naked DNA
• ATP production occurs in the plasma membrane I mesosomes
• Some have flagella
• Diameter of cell is 0.5~5 micrometres

Question 21

Examples of helpful prokaryotes (4)

Answer 21

• Making cheese and yoghurt (lactobacillus)
• In mammalian intestines, they help produce vitamin K and digestion
• Human skin is covered in a ‘normal flora’ o bacteria that prevents pathogens from getting into the body
• Sewage treatment