Biology - Topic 1 - Cell Biology Flashcards
(121 cards)
1
Q
What are eukaryotic cells?
A
Cells which contain a nucleus
2
Q
Whats a prokaryotic cell?
A
Cells which dont contain a nucleus
2
Q
What are organism’s which are made from eukaryotic cells called?
A
Eukaryotes
3
Q
What are organism’s which are made from prokaryotic cells called?
A
Prokaryotes
3
Q
Difference between Eukaryotes and Prokaryotes?
A
Eukaryotes are usually multicellular, whereas prokaryotes are single celled
4
Q
Whats the function of a nucleus
A
A nucleus holds all genetic material needed to control the cell activities
5
Q
Whats the function of a mitochondria?
A
Contain’s enzymes needed for respiration, to release energy
5
Q
What’s the function of a cytoplasm?
A
Jelly-like substance which contain’s nutrients, salts and enzymes required for chemical reactions
6
Q
Whats the function of a semi-permeable cell membrane?
A
Control what comes in and out of cells
7
Q
What’s the function of a ribosomes?
A
Production of proteins
7
Q
What’s the function of a cell wall?
A
Provides protection and structure to the cell
7
Q
What extra features do plant cells have which animal cells don’t?
A
Cell wall, vacuole, chloroplasts
8
Q
What’s the function of a vacuole?
A
Holds weak solution of sugar and salts called cell sap to keep the cell swollen
8
Q
Whats the function of a chloroplast?
A
Site of photosynthesis
8
Q
What are cell walls made of?
A
Cellulose
9
Q
What other cell also have features of a cell wall
A
Algal Cells
9
Q
What does chloroplasts contain?
A
Chlorophyll, a green pigment ,which absorbs light and specific enzymes that are needed for photosynthesis and food to be produced
9
Q
Where is the genetic material in a prokaryotic cell?
A
The genetic material is free in the cytoplasm
9
Q
What does a prokaryotic cell contain?
A
Circular strand of DNA, Cell membrane, cell wall cytoplasm and occasionally a plasmid
9
Q
What’s the function of a plasmid?
A
Small ring of DNA
9
Q
What does bacterial cells sometimes contain?
A
Flagella which are hair like structures that help the bacteria move
9
Q
Whats differentiation of a cell?
A
Cells develop subcellular structures to perform its job
9
Q
When does differentiation happen in animal and plant cells
A
In animal cells, most cells differentiate in the early stages of its life
However for plants the ability to differentiate is never lost
9
Q
What are stem cells?
A
Undifferentiated cells which have the ability to develop into any cell
9
What is the function of a sperm cell?
Designed for the effective transport of male DNA to female DNA for sexual reproduction
10
Function of the head of a sperm cell??
The head contains all genetic information. It also has enzymes to digest the cell membrane
10
How are sperm cells differentiated to perform its job more efficiently?
.Have lots of mitochondria for energy for more movement time
.Has a tail to swim
Have enzymes to digest the cell membrane
11
What are the function of nerve cells?
Carry electrical impulses
12
Why do muscle cells need to be specialised?
To contract quickly
13
How are nerve cells specialised
Carry electrical impulses rapidly
Long axon to carry impulses for long distances
Branched at both ends to connect and pass signals between one another
Insulated of fatty sheath to help impulse move quicker
14
How are muscle cells specialised
Contain lots of mitochondria to provide energy for contraction and have protein filament to help slide over and contract.
15
Why are xylem cells specialized?
Form xylem vessels to transport water and dissolved ions
15
Where are root hair cells found
Plants roots to increase surface area for more efficient absorption
15
How are root hair cells specialised?
Vacuole full of cell sap which is more concentrated than soil water creating a water potential gradient and more efficient water absorption
Lots of mitochondria to provide energy for active transport of mineral ions from the soil
16
What are root hair cells specialised for?
Exchange surface to absorb water and nutrients from the soil
17
Difference between xylem and phloem cells
Phloem cells are living where as xylem cells are not
18
What are phloem cells specialized for?
Transport of sugars and amino acids around the plant. Cells are joined to joined with sieve plates between them to allow passage of substances
18
How have xylem cells been specialized?
Xylem are dead and hollow, and don't have a top and bottom cell wall, subcellular structures or cytoplasms for water to be drawn upwards
19
Magnification and resolution of a Light Microsope
Magnification : 1500x
Resolution: .2 Micrometre
19
What did light microscopes allow to do?
View individual cells and their larger subcellular structures such as a nuclei
19
How do light microscopes work?
Use light and senses to create a magnified image of a specimen.
20
What are electron microscopes?
Use electron beams
21
Difference between a Light and Electron microscope
Electron beams have smaller wavelengths than light beams
Electron has a higher magnification and resolution power
22
What do electron microscopes allow you to see which, light microscopes don't?
Mitochondria, chloroplasts, nuclei and ribosomes and plasmids
23
What's resolution
Ability to distinguish between two points
24
What are chromosomes?
Coiled up DNA found in the nucleus
25
What process do eukaryotic cells use to divide?
Mitosis
25
What are genes?
section of DNA which control development of specific characteristics
26
What is produced during mitosis?
2 Daughter cells which are identical to the original cell and have the same number of chromosomes
27
What happens during the growth phase in the cell cycle
The cell grows and replicates all subcellular structures (mitochondria and ribosomes)
Duplicated all DNA so each cell has the same DNA
27
What happens to the DNA when it is about to divide and when it isn't?
Not dividing: DNA is spread out in long strings getting ready for mitosis
Dividing: Form X-Shaped chromosomes with both sides containing same DNA
28
What happens during mitosis?
Nuclear membrane breaks down and chromosomes line up at the equator of the cell
Fibre breaks apart the arms of the chromosome to opposite sides of the cells
Membranes form around the chromosome to create nuclei for the cells
Cytoplasm and cell membrane divide producing 2 identical daughter cells
29
What is the process which the cytoplasm and cell membrane divide called?
Cytokinesis
30
What's the importance of mitosis?
Grow and replace damaged cells
30
What is binary fission?
Method on how prokaryote cells divide and reproduce
31
When is mitosis demonstrated?
Zygotes undergo several rounds of mitosis to increase number of cells and develop into embryos . Embryos then go through more rounds of mitosis and differentiation to create foetuses
32
What process do organisms which produce asexually go through?
Mitosis
33
What conditions are speed of division dependant on?
Temperature and nutrient concentrations
34
What's the process of binary fission?
The genetic material stored in the circular DNA and plasmids get replicated
Cell begins to expand and circular DNA move to opposite sides of the cells
Cytoplasm divides, and cell wall forms around 2 new daughter cells
35
What is produced from binary fission?
2 Daughter cells, with a copy of circular DNA and variable number of plasmids
36
What is the mean division time?
Time for one bacterial to divide once
37
Formula for number of divisions
Time spent dividing/ Mean division time
38
Formula for cells produced
2^Number of divisions
38
How can bacterias be produced?
Petri dishes which contain a growth medium
39
What is a growth medium?
All molecules needed for a cell to grow, which can be a nutrient broth solution or agar jelly
39
What is created when bacteria is grown on agar jelly?
Colony's of bacteria will be made on the surface
40
What are key aspetic techniques in order to create uncontaminated cultures?
Wash your hands and work surface
Growth media must be heated to kill bacteria
Growth media must be added to a sterile petri dish
All work should be done in presence of a Bunsen burner on a yellow flame to create a convection current to prevent contamination in the air
Use Bunsen burner to sterilize inoculating loop
Lid of petri dish must be taped on
Petri dish must be stored upside down
Dish should be incubated at 25oC
41
What does larger the inhibition zone mean?
The treatment is more effective
42
What are inhibition zones?
Area of dead bacteria
43
How can inhibition zone size increase?
Increasing the concentration of the solution
44
What would you see if a bacteria is antibiotic resistant
No inhibition zone would be present
44
Required practical for Investigating the effects of antiseptics and antibiotics on bacterial growth.
Pour hot agar into a sterile petri dish, and leave to cool and set
Use sterile dropping pipette and spreader to evenly spread the bacteria
Soak paper disks in different concentrations of antibiotic or antiseptics for same length of time and place them evenly distributed on the agar plate
Place a disk that's been soaked in sterile water onto the plate
Tape lid onto petri dish and incubate upside down for 48 hours
45
Where are plant stem cells found?
In the meristem
46
What can stem cells be used for?
Produce many cloned plants quickly and economically
47
What is the advantage of using stem cells to clone plants?
Prevent extinction of rare plants
Grow large number of cloned crops with advantageous features such as disease resistance
48
What can Embryonic stem cells cure?
Used to treat type 1 diabetes
Paralysis
48
Where can stem cells be found in human adults?
Bone marrow
49
What can human embryo cells be used for?
Can be cloned in a lab and made to differentiate into specific cells needed for research or to cure diseases
50
Why are human embryos used for research?
Contain stem cells, unlike those found in bone marrow, embryonic stem cells can differentiate into any human body cell
51
What is type 1 diabetes?
People who don't produce enough insulin to regulate their blood sugar levels
51
Whats an issue with using embryonic stem cells as a treatment method?
The body can often reject the transplanted cells
51
How can embryonic stem cells be used to treat paralysis?
Embryonic stem cells can differentiate to functional nerve cells which get transplanted into the damaged areas
52
How is paralysis caused?
Damage to nerve cells in the spinal cord
52
How can embryonic stem cells be used to treat diabetes?
Can differentiate into insulin producing pancreatic cells and then transplanted into the patient
53
Advantage of Therapeutic cloning?
The cells produced wont be rejected by the patients body
53
What is Therapeutic cloning?
Stem cells are made with the same genetic information as the patient.
53
What are risks with stem cells grown in labs?
Can become contaminated with viruses which are passed onto the patient
54
What is diffusion of water called?
Osmosis
54
How do particles move in and out of the cell membrane?
Substances diffuse across the cell membrane
54
What is diffusion?
Net movement of particles from an area with high concentration to an area with low concentration
55
Ethical and moral issues with stem cell research?
People believe embryos are potential life and should not be used for treatment
People believe curing ill people is more important than embryos which are faulty and will be probably destroyed and should be used instead
56
What does partially permeable imply?
Only certain substances are able to diffuse across them
56
Examples of diffusion
Oxygen and carbon dioxide diffuse in and out of the cells during gas exchange
Waste products such as urea diffuse out of cells into the blood plasma to be excreted in the kidney
57
What happens if a substance is too large to diffuse through the cell membrane?
They get digested and become small enough to diffuse
58
What is rate of diffusion?
How much substance is diffused in a given time
58
What is rate of diffusion affected by?
Temperature
Concentration gradient
Surface area of membrane
58
How does a concentration gradient affect rate of diffusion
The bigger difference between concentrations of each side, the faster the particles move
58
How does temperature affect the rate of diffusion?
Particles have more kinetic energy and move around quicker
59
Surface area to volume ratio of multicellular organisms
Have very small surface area to volume ratio. Means they require highly adapted exchange surfaces and transport systems to provide the cells with everything they require
60
How does a membrane having a larger surface area affect rate of diffusion?
More particles can pass through the membrane at the same time
60
Surface area to volume ratio of single celled organisms
Substances don't have to travel far to get where they need to be and simple diffusion such as osmosis and active transport are sufficient
60
How is the small intestine wall been adapted?
Lined with finger like projections called villi which increase the surface area of the small intestine walls and quicker absorption
61
What does each villus contain and whats the advantage?
Has a single layer of surface cells and a vast network of capallaries
Advantage: Molecules from the small intestine have a short diffusion distance into the blood and the concentration gradient is constantly maintained
62
Function of the lungs?
Take in oxygen from the air so it can be carried by the blood to cells that require it for aerobic respiration. Also remove carbon dioxide from the blood and send it back into the air
63
How have lungs been adapted
Contain lots of tiny air sacs called alveoli which allow for efficient gas exchange
64
Advantages of alveoli in the lungs?
Provide massive surface area
Moist lining to disolve gases
Have very thin walls for short diffusion distances
Good blood supply to maintain concentration gradient
65
How does the gills work?
Water flows into the mouth and over the gills where oxygen diffuses into the blood and carbon dioxide does the reverse
66
How has the structure of fish gills been adapted for efficient gas exchange?
Each gill has many thick gill fillaments which are covered in lamellae to provide massive surface area
Water flows opposite direction of the blood so a large concentration gradient is maintained and maximum oxygen is absorbed from the water
67
How has the lamallae been adapted also?
Have excellent blood supply ( Capillary networks) and a thin layer of surface cells for short diffusion distance
68
How have leaves been structured in order to perform there job?
Structured to allow oxygen and water vapour to diffuse out of cells and carbon dioxide to diffuse into
69
Whats the first exchange surface of a plant?
The underside of the lead Is an exchange surface between air and air spaces. Is covered in tiny holes called stomata
70
What is a stomata?
Tiny openings or pores in plant tissues which allow for gas exchange
71
What are stomatas?
Tiny holes which allow carbon dioxide to enter, and oxygen and water vapour to leave, down concentratiom gradients
72
How are stomatas controlled?
Guard cells.
They close the stomata when the plant is losing more water than recieving to prevent wilting
73
What is the second exchange surface of a plant
The cell walls.
They allow carbon dioxide to diffuse into the cells for photosynthesis and oxgyen and water vapour out. The air spaces surrounding the leaf cell increase the area in which gas exchange can take place
74
How have plant roots been adapted?
Have specialised cells called root hair cells, which are adapted for efficient absorption of water and mineral ions from the soil
Root hair cells increase surface area
75
How has the inside of an plant root been adapted?
Vacuole full of concentrated cell sap creates a steep water potential gradient
Contain lots of mitochondria for active transport of mineral ions
76
What is osmosis?
Movement of water particles across a partially permeable membrane, from a region of high concentration to area of low concentration
77
Does osmosis require energy?
Requires no cellular energy
78
What is active transport?
Allow substances to move from an area of low concentration to an area of high concentration, against the concentration gradient
79
What is required for active transport
Requires energy from respiration
Transport proteins on cell membranes use the energy to move substances against concentration gradients
