Cell cycle, growth, death, and differentiation

Question 1

Differences between proyaryotic and eukaryotic cells

Answer 1

Eukaryotic cells
- Bigger
-Contain membrane bound, fluid filled compartments called organelles
-They’re more complex
-Can be multicellular or unicellular: fungi, plants, animals, protists

Prokaryotic cells
- Unicellular: bacteria and archaea
-Most prokaryotic cells have cell walls, whereas only some eukaryotic cells have cell walls, such as animals don’t.
- No nucleus to contain DNA
- No membrane bound organelles

Question 2

Similarities between proyaryotic and eukaryotic cells

Answer 2

• both have DNA
• Both have ribosomes
• Both have cytoplasm
• Both have plasma membrane (cell membrane)

Question 3

What are living things

Answer 3

No real consensus or definition, but characteristics often used to describe an organism are:
- Organised structure
- Homeostasis
- Movement
- death
- composed of cells
- responsiveness to stimuli
- metabolism
- growth
- reproductive capacity

Question 4

Whats the three domain hierarchy and why necessary?

Answer 4

A classificaition system that Carl Woese introduced in 1990. Domain is the classificiation level above kingdom, and Woese argued it was necessary because although Archaea and Bacteria are both proyaryotic, Archaea are closer related to Eukaryotic than Bacteria.

Question 5

What are the 4 main shapes of proyaryotes?

Answer 5

1. Round balls (cocci)
2. Rod shaped (Bacilli)
3. Banana shaped (Vibrio)
4. Corkscrew shaped (Spirochaetes)

Question 6

What do you call the 4 arrangements of projaryote cells?

Answer 6

Pairs: Diplo…
Chains: Strepto….
Bunches: Staphlo….

Question 7

Why are viruses not usually considered living?

Answer 7

Living things have metabolic processes, but viruses do not.

Question 8

Differences between plant and animal cells?

Answer 8

Plant cells have that animals dont:
- Cellulose cell wall
- Large vacuole
- Plasmodesmata
- Chloroplasts

Animal cells have that plants dont:
- Centrosome
- Lysosomes

Question 9

Whats the name of the folded inner membrane of mitochondria and purpose of it

Answer 9

Cristae
Increases surface area, allowing for more efficient ATP production through cellular respiration

Question 9

What organelles are bound by a double membrane?

Answer 9

• Mitochondria and chloroplasts

Question 10

Why is the intestinal wall made up of many small cells than than few big?

Answer 10

Small cells have larger SA:V ratio than larger cells of same shape. Since cells must exchange materials with their environment through the membrane, a larger SA:V ratio therefore increases the rate at which cells in the intestine can absorb food.

Question 11

Whats the acronym in which you can define life?

Answer 11

Movement
Respiration
Stimuli
Grown
Reproduction
Excretion
Nutrition
DNA

MRSGREND

Question 12

Cell Theory States:

Answer 12

• All oganisms are composed of cells (unicellular or multicellular)
• All cells come from pre-existing cells (biogenesis)
• Cells are the smallest living organisational unit

Question 13

True or false: Prokaryotes have a small SA:V ratio

Answer 13

False, because they’re small, they have a large SA:V ratio

Question 14

True or false: Eukaryotes have a small SA:V ratio

Answer 14

True

Question 15

Where can you find Archaea

Answer 15

In extreme conditions (temperature, PH, salinity) eg. underwater volcanoes

Question 16

All cells have:

Answer 16

• cell membrane
• cytoplasm
• DNA
• Ribosomes

Question 17

Fill in blank:

Larger cells have a ___ (lower or higher) SA:V ratio
Smaller cells have a ___ (lower or higher) SA:V ratio
High SA:V = ___(efficient or inefficient) transport
Low SA:V = ___(efficient or inefficient) transport

Answer 17

a) lower
b) higher
c) efficient
d) inefficient

Question 18

What happens if you increase SA without increasing V?

Answer 18

1) More efficient transport as it reduces amount of exchange needing to occur across plasma membrane. Also creates more space for membrane bound enzymes helping create cell activity.
2) Flattened shape. Decreases distance that substances need to be transported from centre of cell to plasma membrane. This is seen in cells needed for rapid transport of substances like red blood cells (look penut shaped)

Question 19

What are the benefits of organelles as internal compartments?

Answer 19

• Increased efficiency
• Makes cells less vulnerable to external changes

Question 20

Describe the role of the cell membrane (Plasma Membrane)

Answer 20

• Provides barrier between internal and external environment
• Controls what substances enter and exit cell
• Generally composed of a lipid bi-layer (2 layers of lipids) and a number of transport proteins

Question 21

Describe the role of the cytoplasm and cytosol

Answer 21

• Cytoplasm is fluid and organelles outside nucleus (all contents for prokaryotes)
• Liquid portion of cytoplasm is called cytosol
• Cytosol is where many chemical reactions happen in cell

Question 22

Describe the role of the nucleus

Answer 22

• Surrounded by nuclear membrane that has pores
• Contains a nucleoulus where ribosomes area assembled
• Contains DNA in form of linear chromosomes which become visible during cell division
• Genes are segments of DNA that contain the info for the synthesis of proteins

Question 23

Describe the role of the mitochondria

Answer 23

• Present in all eukaryotic cells
• Contains DNA
• Very active cells contain many mitochondria (eg Heart)
• Site of earobic respiration (production of APT)

Question 24

What is ATP

Answer 24

Adenosine Triphosphate: The energy molecule thaty your body uses to power metabolic reactions

Question 25

Describe the role of the ribosomes

Answer 25

- very small, only visible under electron microscope - composed of proteins and ribosomal RNA (rRNA) - not surrounded by a membrane - The site of protein synthesis - Can be found free in cytoplasm or attached to rough ER - Free ribosomes make proteins that'll function in the cytoplasm - Rough ER ribosomes make proteins that are secreted out of the cell, packaged into organelles or inserted in cell membranes.

Question 26

Describe the role of the Endoplasmic reticulum

Answer 26

- Network of intracellular membraneous sacs (cisternae) and tubules that link to the plasma membrane and the nucleus - can be rough (with ribosomes) or smooth

Question 27

A cell which has been infected by a virus may die by:

Answer 27

either apoptosis or necrosis.

Question 28

True or false: During apoptosis, a release of cytoplasm into the extracellular fluid takes place

Answer 28

False, the cytoplasm contains lots of things, which inside cell are god, but if they get out of cell into extracellular fluid, or internal environment (fluid outside cell) they can often have a toxic effect on the cells around them.

Question 29

Mutations to the p53 gene has been linked to a predisposition to a number of types of cancer. The reason for this is that a defect in the p53 protein results in:

Answer 29

a lack of cell sensitivity to TRAIL.

Question 30

What is TRIAL

Answer 30

A death ligand. If a TRIAL binds to a receptor on the surface of a cell, it's going to instruct the cell to die by apoptosis.

Question 31

What are the 4 bases of DNA

Answer 31

Cytosine, guanine, adenine, and thymine

Question 32

What are stem cells

Answer 32

A cell thats undifferentiated or patially differentiated, that is, its capable of differentiating to give rise to different kinds of cells. Like a kid, they're able to specialise further, and choose what course they want to pursue.

Question 33

What is the potency of a stem cell

Answer 33

It's ability to differenciate to become more different kinds of cells. The more potent it is, the more different kinds of cells it can give rise to.

Question 34

Difference between totipotent and pluripotent stem cells

Answer 34

If totipotent, means it can differentiate to become any kind of cell in the embryo, but can also differentiate to become an extra embryonic cell like placenta or umbilical cord. Whereas pluripotent can divide to become any cell in the body, but it can't differentiate to become placenta for example.

Question 35

DNA polymerase III extends primers in what direction

Answer 35

5’ – 3’ direction

Question 36

Where is DNA found in eukaryotic cell

Answer 36

Nucleus

Question 37

Where is DNA found in prokaryotic cell

Answer 37

Nucleoid

Question 38

Define osmosis

Answer 38

the passive net movement of free water molecules from a place with a high concentration of water (low solute concentration) to a place with a low concentration of water (high solute concentration) through a semi permeable membrane

Question 39

What does passive mean

Answer 39

doesn't require energy - true of osmosis and true of simple diffusion

Question 40

what does net mean (passive net moveent)

Answer 40

the overall. (in osmosis, the odd water molecule might move the opposite direction of the flow, but overall the water molecules will move from area of high concentration of water to a place with a low concentration of water).