Biology #1 Cell biology

?
  • Created by: MBid89
  • Created on: 23-04-18 10:53
What are the 2 main phases of cell cycles?
Interphase and cell division (including mitosis & cytokinesis)
1 of 34
What happens during interphase? (3)
Number of mitochondria & chloroplasts (in plants) increases as they grow & divide. Growth. Protein synthesis.
2 of 34
What happens during each stage of interphase?
G1: growth of cell (increase in size), new proteins & organelles made. S: DNA synthesis (replicates all genetic material). G2: Double checks for errors in copying, prepares for cell division
3 of 34
What is the role of cyclins in cells?
They are proteins that ensure that taste are performed at the correct time. Cell does not progress into a new phase/ stage until the corresponding cyclin (4 main types in humans) has reached a threshold concentration.
4 of 34
How do cyclins work?
Bind to enzymes called 'cyclin-dependent kinases'. These become active & attach phosphate groups to other proteins in the cell. This attachment triggers other proteins to become active & carry out tasks specific to that phase in the cell cycle.
5 of 34
Who discovered cyclins?
Tim Hunt, by accident (serendipity), while doing research into protein synthesis in sea urchins.
6 of 34
State cell theory (4)
All living things are made of cells. Cells are the unit of life. New cells come from old cells. Cells contain inherited information.
7 of 34
What are 3 atypical cells & why?
Aseptate fungal hyphae: 1 long undivided tube, polynucleated (despite being surrounded by single plasma membrane). Striated muscle cells: cells fuse to form v long fibres (300m+), polynucleated. Giant algae cell: can be up to 7cm, complex form
8 of 34
How did 19th cent scientists believe cells could be formed?
via 'spontaneous generation' (out of non-living material i.e. air?)
9 of 34
Outline the origin of eukaryotic cells according to endosymbiotic theory
Mitochondria & chloroplasts are similar to prok. Host cell injested another. Symbiotic relationship (supplied ATP or carbon compounds to both itself & host). Division/ binary fission of mito/chloro. Host develop into either heterotroph or autotroph.
10 of 34
What was the aim of Pasteur's experiments?
To falsify spontaneous generation & to support that new cells come from old cells.
11 of 34
Outline Pasteur's experiment
2 groups of swan-necked flasks (prevented organisms in air from entering): 1 with broth, boiled to kill any organisms present, others unboiled. Fungi & other organisms soon appeared in unboiled but not in boiled ones.
12 of 34
What is meant by 'unicellular organisms'?
Organisms that carry out all functions of life in 1 cell i.e. bacterium
13 of 34
Give examples of 2 unicellular organisms
Paramecium (lives in ponds, 0.25mm or less). Chlamydomonas (lives in freshwater habitats, 10-30um)
14 of 34
Give details of nutrition and response (i.e. movement) of paramecium & chlamydomonas. State whether they respire or photosynthesise.
Paramecium: nutrition: ingests & digests smaller organisms (heterotroph), response: reacts to stimuli (moves using cilia). Respires. Chlamydomonas: nutrition: photosynthetic autotroph, response: positive phototropism (using eye spot) Photosynthesises
15 of 34
What is meant by 'multicellular organisms'?
Specialised groups of cells have different functions , allowing for cell size (SA to volume ratio) to stay the same while increasing complexity of organism.
16 of 34
What are emergent properties?
Properties that arise from the interaction of the component parts of a complex structure (i.e. memory).
17 of 34
State how differentiation occurs.
Each cell initially has the full genome, so could potentially specialise into any cell. When a cell differentiates only certain genes are expressed, & once this pathway has begun, it mostly cannot change (except in some plants).
18 of 34
What are benefits of unicellular (2) vs multicellular (3) organisms?
Uni: can exist in hazardous areas due to simplistic form. Quick asexual reproduction. Multi: longer life span. Specialised cells (division of labour) that results in emergent properties. Communication between cells.
19 of 34
What are stem cells?
Cells that have the capacity to divide & differentiate along different pathways (pluripotent)
20 of 34
What are pros & cons of embryonic stem cells?
Pros: pluripotent & unlimited growth potential. Cons: could be argued that it is a potential human life being killed; immoral.
21 of 34
What are pros & cons of adult stem cells?
Pros: compatible with adult donor's own tissues, meaning less chance of a tumour/ rejection by body. Cons: Only a limited capacity to differentiate, less growth potential & difficult to obtain (bone marrow, skin & liver)
22 of 34
What are pros & cons of umbilical cord blood stem cells?
Pros: umbilical cord is normally discarded whether or not cells are taken. Cons: newborn babies cannot give informed consent for cells to be taken from umbilical cord (although parents can).
23 of 34
What are the 2 textbook therapeutic uses of stem cells (SCs)?
Stargardt's disease (muscular dystrophy) genetic disease in children, loss of vision. Embryonic SCs injected into eyes & develop into retina cells. Leukaemia: cancer cells cause excess of WBCs. Adult SCs from pelvis marrow, give them chemo, reinject
24 of 34
Define 'resolution'
the smallest distance between 2 objects at which they can still be distinguished
25 of 34
Define 'magnification'
the increase in size of an image until the point above which the image can no longer be focused sharply
26 of 34
What is a micrograph?
A photograph taken down the microscope
27 of 34
What is the formula for calculating magnification?
Magnification= size of Image/ size of Actual specimen (MIA)
28 of 34
How many mm in a um?
1000 (e.g. 1mm=1000um & 1um=0.001)
29 of 34
Why do electron micrographs have a better resolution than light micrographs?
Because electrons have a much shorter wavelength.
30 of 34
Outline features (i.e. things about it) of prokaryotic cells (3)
Simple cell structure "before nucleus" (not compartmentalised); no membrane bound organelles (free DNA called 'nucleoid'; replicates by binary fission
31 of 34
What are structures of a prokaryote that a eukaryote doesn't have? (4)
Flagellum, 70S ribosomes, naked DNA, pili
32 of 34
Outline how prokaryotes replicate
Binary fission (splitting in two). DNA & organelles are replicated & move to opposite poles of cell. Cell wall & plasma membrane are pulled inwards so the cell pinches apart to form 2 identical cells.
33 of 34
What is the advantage of compartmentalisation in eukaryotes?
Biochemical reactions (using enzymes & substrates) can be concentrated in a small area & separated from each other.
34 of 34

Other cards in this set

Card 2

Front

What happens during interphase? (3)

Back

Number of mitochondria & chloroplasts (in plants) increases as they grow & divide. Growth. Protein synthesis.

Card 3

Front

What happens during each stage of interphase?

Back

Preview of the front of card 3

Card 4

Front

What is the role of cyclins in cells?

Back

Preview of the front of card 4

Card 5

Front

How do cyclins work?

Back

Preview of the front of card 5
View more cards

Comments

No comments have yet been made

Similar Biology resources:

See all Biology resources »See all Cellular processes and structure resources »