Life at a Cellular Level 1 Flashcards Preview

Science for Medicine > Life at a Cellular Level 1 > Flashcards

Flashcards in Life at a Cellular Level 1 Deck (45)
Loading flashcards...
1
Q

What is a cell?

A

Functional unit of all living things

2
Q

Describe a prokaryotic cell.

A
  • Bacteria
  • Lack nuclear membrane
  • No mitochondria
  • No membrane bound structures
3
Q

Describe a eukaryotic cell

A
  • Human cells
  • Multicellular animals and plants
  • Nucleus with membrane
  • Membrane bound structures
4
Q

What are stem cells?

A
  • Multipotent: Cells that can differentiates into many cells

- Pluripotent: Cells that can differentiate into all cell types of the body

5
Q

What are changes in gene expression reflected in?

A

The alteration of cell structure and behaviour

6
Q

What process can some cells go through during differentiation?

A

Cell fusion

7
Q

What are cancer cells?

A
  • Cells that divide without any control and fail to coordinate with normal cells.
  • Fail to differentiate into specialised cells
  • Displace and replace the normal cells
8
Q

What is apoptosis?

A
  • A process of programmed cell death

- A central mechanism controlling multicellular development

9
Q

What are tissues?

A

Functional arrangements of cells

10
Q

What are organs?

A

Mixture of different tissues

11
Q

What are systems?

A

Cells or organs with similar functional roles

12
Q

What is the cell membrane?

A

-Selective barrier

13
Q

What does the plasma membrane detect?

A

Chemical messengers and signalling molecules from surrounding cells or other organs

14
Q

How can membrane lipids be described.

A

Amphipathic

-Hydrophilic head and hydrophobic tail

15
Q

What are the functions of the plasma membrane?

A
  • Transport
  • Surface of enzymatic activity
  • Receptors for signal transduction
  • Intercellular joining
  • Cell-cell recognition
  • Attachment to cytoskeleton and ECM
16
Q

Describe passive diffusion.

A
  • Concentration gradient needed

- Lipid-soluble molecules pass freely (non-polar)

17
Q

Describe facilitated diffusion

A
  • Concentration gradient needed

- Requires carrier molecules

18
Q

What do tight junctions do?

A

Seals gap between epithelial cells

19
Q

What do adheren junctions do?

A
  • Connects actin filament bundle in one cell with that in the next cell
  • Link actin filaments in two different cells
20
Q

What do desmosomes do?

A
  • Connect intermediate filaments in one cell to those in the next cell
  • Link keratin filaments in two different cells
21
Q

What do gap junctions do?

A
  • Allows the passage of small water soluble molecules from cell to cell
  • Links two cells cytoplasm together
22
Q

Where would you find tight junctions?

A
  • Intestine
  • Kidney
  • Blood brain barrier
23
Q

What are tight junctions dependent on?

A

Calcium

24
Q

Where would you find gap junctions?

A
  • Heart muscle
  • Liver
  • Pancreas
25
Q

What are gap junctions composed of?

A

Connexions (6 subunit membrane spanning proteins)

26
Q

What are the 4 types of cell signalling?

A
  • Contact-dependent
  • Paracrine (cell only signals local cells)
  • Synaptic (specific to neurones)
  • Endocrine (signal gets carried around body and has mass effect
27
Q

What does fast cell signalling involve?

A

Adrenaline or nerves

28
Q

What does slow cell signalling involve?

A

Genes being switched on/off

29
Q

Describe the structure of a mitochondria?

A
  • Porous outer membrane
  • Inner membrane with cristae
  • Matrix containing calcium binding sites and enzymes for oxidation of food molecules.
  • Circular DNA
  • Ribosomes
30
Q

What does the nucleus contain?

A
  • DNA
  • Nucleoprotein
  • RNA
31
Q

What are nucleoli?

A

Sites of ribosomal RNA synthesis and ribosomal assembly

32
Q

What 2 forms does DNA come in?

A
  • Heterochromatin

- Euchromatin

33
Q

Describe the nuclear membrane of the nucleus.

A
  • Phospholipid bilayer
  • Encloses the nucleus
  • Contains pores
  • Closely associated with the ER
34
Q

Describe the ER.

A
  • Membrane bound

- RER has ribosomes

35
Q

What is the ER responsible for?

A

Protein modification and transport coordinated by the RER and Golgi body

36
Q

What does the smooth ER do?

A

Mainly breaks down compounds such as drugs and glycogen or synthesises some compounds such as lipids

37
Q

What are lysosomes used for?

A
  • Used to separate enzymes from the rest of the cell

- Used in autophagy or digestion of engulfed particles.

38
Q

What does the cytoskeleton do?

A
  • Supports and maintains cell shape
  • Holds organelles in position
  • Moves organelles
  • Involved in cytoplasmic streaming
  • Interacts with extracellular structures to hold cell in place
39
Q

What are the 3 different divisions to the cytoskeleton?

A
  • Microfilaments
  • Intermediate filaments
  • Microtubules
40
Q

What are microfilaments involved in?

A

Cell dynamics

41
Q

What are intermediate filaments involved in?

A

Hold organelles in place

42
Q

What are microtubules involved in??

A

Mitosis and meiosis

43
Q

What are cilia and flagella made from?

A

Microtubules

44
Q

What are cilia?

A
  • Short
  • Usually many present
  • Move with stiff power stroke and flexible recovery stroke
45
Q

What are flagella?

A
  • Longer
  • Usually one or two present
  • Movement is snakelike