(Done) Cell Biology (Paper 1) Flashcards
(50 cards)
1
Q
Animal cells subcellular structures
A
- Nucleus
- Mitochondria
- Ribosomes
- Cytoplasm
- Cell membrane
2
Q
Plant cell extra subcellular structures
A
- Rigid cell wall
- Permanent vacuole
- Chloroplasts
3
Q
Bacteria subcellular structures
A
- DNA contained within a single circular strand
- May also contain one or more small rings of DNA called plasmids
- Cell membrane
- Cell wall
- Cytoplasm
4
Q
How do light microscopes work
A
- They use light and lenses to form an image of a specimen and magnify it
5
Q
How do electron microscopes work
A
- They use electrons instead of light to form an image
6
Q
What can light microscopes see
A
- Large subcellular structures
- Individual cells
7
Q
What can electron microscopes see
A
- The internal structure of mitochondria and chloroplasts
- Smaller subcellular structures such as plasmids and ribosomes
8
Q
Calculation for magnification
A
Magnification = image size / real size
9
Q
Define differentiation
A
- The process by which a cell changes to become specialized for its job
10
Q
What happens in differentiation
A
- Cells develop different subcellular structures and turn into different types of cells which allows them to carry out specific functions
11
Q
When does differentiation happen in animals and plants
A
- Animals - The ability to differentiate is lost at an early stage after specialization
- Mature animals - Differentiation only occurs for the repair and replacement of cells such as skin or blood cells
- Plants - lots of plant cells retain the ability to differentiate throughout life
12
Q
Sperm cell specialisation
A
- Long tail and streamlined head to help it swim
- Lots of mitochondria to give it the energy to swim
- Enzymes in the head to digest through the egg cell membrane
13
Q
Nerve cell specialization
A
- long to cover more distance
- Have branched connections to form a large network across the body
14
Q
Muscle cell specialization
A
- Long fibers so they have space to contract
- lots of mitochondria so they have energy to contract well
15
Q
Root hair cell specialization
A
- Long projections to increase surface area to absorb mineral ions and water better
16
Q
Xylem and phloem specialisation
A
- To form tubes cells are joined end to end
- Xylem cells are hollow in the center to allow things to flow through it
- Phloem cells have very little sub cellular structures to allow things to flow through them
17
Q
What are chromosomes
A
- Coiled up lengths of DNA molecules contained within the nucleus
18
Q
What is the cell cycle
A
- When body cells in multicellular organisms divide to produce new cells
19
Q
Why do cells undergo mitosis
A
- For growth
- To replace damaged cells
20
Q
What happens in growth and DNA replication stage within the cell cycle
A
- The cell must grow and increase the amount of sub cellular structures like mitochondria and ribosomes
- The DNA is duplicated and forms x shaped Chromosomes
21
Q
What happens in the mitosis stage within the cell cycle
A
- The chromosomes line up at the center of the cell and the cell fibers pull them apart
- Membranes form around each of the sets of chromosomes, these become the nuclei of the two new cells
- The cell membrane and cytoplasm divide
- The two daughter cells are identical
22
Q
What happens during binary fission
A
- The circular DNA and plasmids replicate
- The cell gets bigger and the circular DNA strands move to opposite poles of the cell
- The cytoplasm begins to divide and new cell walls begin to form
- The cytoplasm divides and two daughter cells are produced, they will have the same circular strand of DNA but varying amount s of plasmids
23
Q
What factors can increase the speed of binary fission
A
- Warm environment
- Lots of nutrients
24
Q
What are lab grown bacteria grown in
A
- Culture medium
25
What is a culture medium
- A medium which contains the correct resources for optimum bacteria growth
26
List culture mediums
- Nutrient broth solution
- Agar jelly
27
What temperature are bacteria typically cultured at in schools and why
- Below 25 C as harmful pathogens are likely to grow at this temperature
28
What temperature are bacteria typically cultured at in industrial situations and why
- Above 25 C as the bacteria will grow faster
29
Define inhibition zone
- A clear are left behind due bacteria dying from contact with an antibiotic
30
How to sterilize equipment
- Heating at a high temperature
31
Where can stem cells be found in humans
- Early embryos
- Bone marrow
32
How can stem cells be used to treat disease
- Bone marrow transfer
- Replace faulty cells
33
Arguments against stem cell research
- Human embryos have potential for life so shouldn't be experimented on
34
Arguments for stem cell research (2)
- Treating suffering patients is more important than the rights of embryos
- Embryos in research are traditionally unwanted ones from fertility clinics that would be destroyed anyway
35
Where and when can stem cells be found in plants
- In the meristem
- The entire duration of a cells life
36
How can stem cells be used with plants
- To clone entire plants quickly and cheaply
- Grow mass batches of plants with certain characteristics e.g. disease resistance
37
Define diffusion
- Net movement of particles from an area of high concentration to an area of low concentration
38
Factors affecting diffusion rate
- Concentration Gradient
- Temperature
- Surface area
39
What substances traditionally pass through a partially permeable membrane of a cell
- Oxygen
- Glucose
- Amino acids
- Water
40
Define Osmosis
- Net movement of water particles across a partially permeable membrane from an area of high water concentration to an area of low water concentration
41
Define active transport
- Substance moves from an area of low concentration to an area of high concentrations, across a partially permeable membrane. This process requires energy produced from cell respiration.
42
Uses of diffusion in the body
- Oxygen and carbon dioxide diffusing between cells in gas exchange
- Urea diffusing from cells to blood plasma for removal from the body by kidneys
43
Where does gas exchange happen in the lungs
- The alveoli
44
Specialisation of the alveoli for diffusion
- Enormous surface area
- Moist lining for dissolving gases
- Very thin walls
- Good blood supply
45
How does a moist lining help gas exchange
- Allows gases to dissolve in water enabling them to diffuse across the cell membrane more easily
46
How does a good blood supply help gas exchange
- Maintains a steep concentration gradient
47
48
How are the villi optimised for diffusion
- Large amount of villi provide large surface area
- Single layer of surface cells
- Very good blood supply
49
How are leaves optimised for gas exchange
- Holes called stomata controlled by guard cells
- Flat shape provides large surface area
50
How are the gills optimised for diffusion
- Gill filaments provide large surface area
- Thin surface layer of cells to minimise diffusion distance
