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Flashcards in Life at the Cellular Level 1 Deck (63):
1

What is every organism composed of?

Cells

2

What are cells?

The functional unit of all living things

3

Why are cells small?

To increase their surface area to volume ratio

4

What are the two types of cells?

Prokaryotic cell

Eukaryotic cell

5

What is a prokaryotic cell?

Cells that do not have a membrane bound nucleus

6

What is a eukaryotic cell?

Cell that consists of a cytomplasm and a defined nusleus bound by a nucleus membrane

7

What are some properties of prokaryotic cells?

Found in bacteria

No nuclear membrane

No mitachondria

No membrane bound structures

8

What are some properties of eukaryotic cells?

Found in human cells, multicellular animals and plants

Nucleus with membrane

Membrane bound structures

9

What are stem cells?

Undifferentiated cell which are capable of giving rise to indefinitely more cells of the same type

10

What are the two types of stem cells?

Pluripotent

Multipotent

11

What are pluripotent stem cells?

Can differentiate into all cell types of the body

12

What are multipotent stem cells?

Can differentiate into many cell types

13

What do all cells contain a complete set of?

DNA

14

What determines which proteins are found within a cell?

The genes within the DNA that are being expressed

15

What are genes?

Sequence of DNA or RNA that codes for a molecule that has a function

16

What happens during differentiation?

Cells pass through a series of changes where changes in gene expression are reflected by alterations of the cells structure and behaviour

17

What is differentiation?

Cells change from one cell type to another by expressing certain genes

18

What properties do cancer cells have?

Divide without any control

Fail to coordinate with normal cells

Fail to differentiate into specialised cells

Displace and replace normal cells

19

What are the processes of cell death?

Apoptosis

Necrosis 

20

What is apoptosis?

Physiological, programmed cell death

21

What is necrosis?

Pathological cell death caused by injury or disease

22

What is the process of apoptosis?

  1. Individual cells are induced to die
  2. Membrane bleb, causing no damage to surrounding cells
  3. Within hours there is no inflammation 

23

What is the process of necrosis?

  1. Groups of cells are induced to die
  2. Membrane ruptures causing damage to surrounding vessels
  3. Within days there is inflammation

24

What are the four types of tissues?

Epithelial

Connective

Nervous

Muscular 

25

What are organs?

Mixture of different tissues

26

What are systems?

Cells or organs with similar functional roles

27

What are cell organelles?

Internal organs of a cell responsible for carrying out specific jobs

28

What are some examples of cell organelles?

Mitochondria

Nucleus (containing nucleolus)

Endoplasmic reticuum

Golgi apparatus

Lysosomes

Robisomes

Nuclear envelope

29

What is mitochondria?

Produce a cells source of ATP

30

What are properties of mitochondria?

Outer membrane contains pores (proteins responsible for high permeability)

Inner membrane has cristae (fold increase surface area to fit in more proteins)

Matrix contains binding sites for calcium and most enzymes for oxidation of food molecules

Synthesise most of their own proteins, self replicate, own ribosomes and their own circular DNA

31

What is the nucleus?

Usually largest organelle, main function is to reunite ribosomal RNA (rRNA) and combine it with proteins, occuring in the nucleoli 

 

32

What are some properties of the nucleus?

Contains DNA, nucleoproteins and some RNA

DNA tends to be in two forms (heterochromatin - tightly coiled inactive chromatin, or euchromatin - open chromatin)

Chromatin is a mass of genetic material composed of DNA

33

What is the nuclear envelope?

Surrounds the nucleus and contains the genetic material?

34

What are some properties of the nuclear envelope?

Made of phospholipid bilayer

Contains pores

Closely associated with the endoplasmic reticulum 

35

What is the endoplasmic reticulum?

Network of tubules continuous from the nuclear envelope which packages up proteins

36

What are the two components of the endoplasmic reticulum?

Rough ER, has ribosomes attatched

Smooth ER, used to breakdown compounds (such as glucose) or synthesise compounds (such as lipids)

37

What is the golgi apparatus?

Complex of vesicles and folded membranes involved in secretion and extracellular transport

Proteins are packaged into vesicles destined for lysonomes, secretory vesicles or the cell surface

38

What are lysosomes?

Packaged up with proteins in a vesicle

39

What are properties of lysosomes?

Contains degradative enzymes

Primary lysosome mixes with phagosomes (vesicle containing substance from phagocytosis) to produce secondary lysosomes which release inside or outside the cell

Used to seperate enzymes from the rest of the cell

40

What are ribosomes?

The site of protein synthesis

41

What are the properties of ribosomes?

Link amino acids together in the order specified by mRNA

Small ribosomal subunit reads the RNA

Large ibosomal subunit joins amino acids to form polypeptide chain

42

43

What is the cytoplasm?

Material within a living cell excluding the nucleus, compromises of the cytosol and the organelles

44

What is the cytosol?

Liquid found inside cells, also known as intracellular fluid (ICF)

45

What are the purposes of the cytoskeleton?

Supports and maintains cell shape

Hold organelles in position

Moves organelles

Interacts with extracellular structures to hold the cell in place

Involved in cytoplasmic streaming

46

What are the three main proteins that the cytoskeleton is composed of?

Microfilaments (made up of strans of protein actin, interacts with strands of other proteins)

Intermediate filament (made up of fibrous proteins organised into tough assemblages that stabilise a cells structure)

Microtubules (long hollow cylanders made up of protein tubulin, consists of two subunits a-tubulin and b-tubulin)

47

What are celia and flagella made up of?

Microtubules which are projected from the cell to move molecules

48

What is the cell membrane?

Semi permeable membrane surrounding the cytoplasm of a cell

49

What are properties of the cell membrane?

Composed of phospholipid bilayer

Embedded with proteins for functionality

50

Are membrane lipids amphipathic?

Yes

51

What does amphipathic mean?

Has both hydrophobic and hydrophillic parts

52

What parts of the cell membrane is hydrophobic and hydrophillic?

Phospholipid heads are hydrophillic and the tails are hydrophobic

53

What are the different ways that proteins can be associated with the cell membrane?

Spam the membrane

Embedded and tunnel all of the way through

Embedded and tunnel part of the way through

54

What are some functions of the cell membrane?

Acts as a selective barrier

Transport (proteins provide channels)

Enzymatic activity 

Receptor (change conformation and initiate chain of reactions)

Intercellular joining

Cell/cell recognition

Attatchment to the cytoskeleton and extracellular matrix (ECM)

55

What are the two forms of transport?

Active transport

Diffusion

56

What are the two types of diffusion?

Passive diffusion (concentration gradient needed, lipid soluble molecules pass freely unless to large)

Facilatated diffusion (concentration gradient needed, requires carrier molecules)

57

What are the two forms of active transport?

Endocytosis (cell taking in matter)

Exocytosis (vesicle contents secreted outside of cell)

58

What is cells sticking together called?

Cell adhesion

59

What are different types of cell adhesion?

Tight junction (physical barrier to diffusion between cells, examples are kidney, intestine and blood brain barrier)

Adhesive junction (adherens junction - link actin filaments in two different cells, desmosomes - link keratine filaments in two different cells)

Gap junction (form channels between cells, link the two cells cytoplasm, example being pancreas, liver and heart muscle)

60

What can disease do to cell adhestion?

Stop them sticking together and cause them to seperate, as seen in cancer

61

What are some examples of cell signalling?

Contact dependent (membrane bound signal molecule)

Paracrine (cell realeases molecule to cells around it)

Synaptic (nervous signals target cells using neurotransmitter)

Endocrine (hormones travelling through blood to target cell)

62

What does a receptor do?

Recieves a molecule and then triggers a series of pathways in response

63

Where are some places you can find receptors?

On the cell membrane or in the cytoplasm