B1 Cells Flashcards
1
Q
Osmosis
A
Particles of solvent(water molecules) passing through a partially permeable membrane from a region of higher concentration to a region of lower concentration
2
Q
Cellulase
A
Breaks down cellulose (plant fibre)
3
Q
Amylase
A
Breaks starch down
4
Q
Tail
A
Faster mobility
5
Q
Starch molecule ->(polymer)
A
Glucose molecule (monomer)
6
Q
Cell membrane
A
Controls substances that goes in and out and holds the cell together
7
Q
Protase
A
Breaks protein down
8
Q
Nucleus
A
Contains genetic material and controls cell activities
9
Q
Ribosomes
A
Protein synthesis
10
Q
Cell wall
A
Strengthens and supports cell
11
Q
Plasmid DNA
A
Carries extra information
12
Q
Mitochondria
A
Releases energy through respiration
13
Q
Active transport
A
Movement of molecules across a membrane into a higher concentration
14
Q
Papain
A
Breaks down small and large protein
15
Q
Chromosomal DNA
A
Contains most of genetic information
16
Q
Chloroplasts
A
Contain chlorophyll which absorb light for photosynthesis
17
Q
Alpha
A
Animal derived enzyme, breaks down protein
18
Q
Diffusion
A
Gradual movement of particles from a higher concentration to a lower concentration - spreading out
19
Q
Lipid molecule ->(polymer)
A
Fatty acids (monomer)
20
Q
Lipase
A
Breaks down fat in dairy
21
Q
Acrosomes
A
Allow sperm cell to break through egg membranes
22
Q
Mitosis stages
A
- Prophase nucleus starts to break down and spindle fibres appear
- End of metaphase, chromosomes are lined up on spindle fibres
- Chromosome copies sever are and move to either end of the spindle fibres anaphase
- Telophase a membrane forms around each set of chromosomes to form nuclei
- Cell surface membrane forms to separate the two cells during cytokinesis. Cell wall form in plant cells
23
Q
Light microscope
A
Use light and lenses to form image and magnify
24
Q
Electron microscope
A
Use electrons to form image - higher resolution (see in more detail e.g structure of mitochondria)
25
Differentiation
Cell changes to become specialised for its job
26
What are undifferentiated cells?
Stem cells
27
Eukaryotic
Complex cells(animal and plant cells) have nucleus
28
Prokaryotic
Smaller and simply cells e.g bacteria
29
Eukaryotes
Organisms made up of eukaryotic cells
30
Prokaryotic
Is a prokaryotic cell(singular)
31
Sub cellular structure
Different parts of the cell
32
Cytoplasm
Where chemical reactions happen. Contains enzymes
33
Mitochondria
Reactions for aerobic respiration takes place. Transfers energy for the cell
34
Ribosomes
Where the protein is made for the cell
35
Rigid cell wall
(Cellulose) supports and strengthens cell
36
Vacuole
Contains cell sap, solution of sugar (keeps cell watered)
37
What is meant by “bacteria has no true nucleus”
Only has a singular strand of DNA
38
Equation for magnification (triangle )
Magnification = image size / real size
39
How are sperm cells specialised
Long tail and streamlined head for speed
Lots of mitochondria for energy
Enzymes in head to digest through egg cell membrane
40
How are nerve cells specialised
Carry electric signals from one part of the body to another.
Long cells > branched connections at ends of cells to connect to other nerve cells to form a network throughout the body
41
What do animal cells contain
Nucleus, cytoplasm, cell membrane, mitochondria, ribosomes
42
What do plant cells contain?
Nucleus cytoplasm, cell membrane, mitochondria, ribosomes, rigid cell wall, vacuole, chloroplasts(which have chlorophyll)
43
How are muscle cells specialised
Contract quickly
| They’re long and have lots of mitochondria for energy so they can contract quickly
44
How are roothair cells specialised
Cells on the surface of plant roots
Long hairs to stick into soil
Large surface area to absorb lots of water and mineral ions
45
How are phloem and xylem cells specialised
They form phloem and xylem tubes, which transport substances like water and food around plants.
Cells are long and joined end to end.
Xylem cells are hollow in the centre
Phloem have few sub-cellular structures > more room to flow
46
Different types of stem cells
Embryonic stem cells
Adult stem cell
Meristem
47
Embryonic stem cells
Turn into any cell type
| Found in embryos (totipotent)
48
Adult stem cells
Grown up stem cells, only form a few cell types (pluripotent, multipotent)
49
Meristem cells
Found in plants. Form other cells, found in tips of shoots and roots
50
How can stem cells help diseases
Use adult stem, cells to replace faulty blood cells with cells from a healthy person
Embryonic stem cells can create insulin producing cells for people with diabetes.
New nerve cells can be made
Some people are against cloning as human embryos are potential life
51
What does the nucleus contain
Contains chromosomes with are genetic information
52
How man pay pairs of chromosomes in a human cell
23
53
What is mitosis
Body cells in multicellular organisms dividing to make new cells. Mitosis is to grow or replace cells (results in two new identical cells to the original)
54
What’s a partially permeable membrane
Membrane with very small holes in it. Only tiny molecule can pass. They can pass in both ways as they move randomly. However it’s more likely water will move to the lesser concentration. There’s a steady net flow of water into the lesser areas
55
What is diffusion
Gradual movement of particles from places with a high concentration to a low concentration ( particles spread out)
Both solutions and bases can freely move about. Gases diffuse through each other.
56
What affects the diffusion rate
Bigger the concentration gradient = faster diffusion rate
Higher temperature = faster diffusion rate(more energy)
Larger surface area = higher diffusion rate
57
Cell membranes and diffusion
Cell membranes hold the cell together and let things in and out. Only small molecules can diffuse through cell membranes (oxygen, glucose, animal acids)
Big molecules can’t (starch, protein)
Particles will flow through to the lower concentration ( they do move randomly so they will go both ways, but if there’s more on one side, there’s a net (overall) movement
58
Active transport and examples in root hair cells and humans
Substances absorbed from a lower to a higher concentration, against the concentration gradient.
E.g root hair cells. The concentration of minerals is higher in the root hair cells then in the soil, so diffusion can’t be used. Instead active transport is. Active transport let’s the plant absorb minerals from a dilute solution.
Humans - used in the gut. Lower concentration of nutrients in the gut than in the blood. Active transport allows nutrients to be taken into the blood, which means glucose can be taken into the blood stream even if the blood has a higher concentration than the gut.
59
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What is meant by Exchanging substances
And examples (lungs, alveoli and villi)
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Part of the body is adapted so substances can diffuse effectively.
The lungs job is to transfer oxygen to the blood and to remove CO2 waste from it. To do this lungs contain millions of alveoli where gas exchange occurs.
Alveoli are specialised to maximise the diffusion of O2 and CO2. They have a large surface areas, moist lining for dissolving gases, thin walls and a good blood supply.
Villi have a really big surface area. The small intestine is covered in villi, they increase in surface area so digested food is absorbed into the blood quicker. Have a single layer of surface cells and a good blood supply
60
Exchange surfaces.
Organism exchange surfaces with their environments. Cells can use diffusion to take in needed substances and remove waste. Carbon dioxide and oxygen are transferred between cells and the environment during GAS EXCHANGE.
Urea diffuses from cells into the blood plasma for removal from the body by kidneys.
How easy it is for a pen organism to exchange substances depends on SA:V
61
surface area to volume ratios
The larger the organism is, the smaller the surface area is compared to its Volume.
For example a cuboid with a height of 2cm, length of 4cm and width of 4cm has a surface area of 64cm squared and a Volume of 32cm cubed. Therefore the SA:V ratio is 64:32 which is 2:1. Therefore it’s surface area is larger compared to Volume.
A cube with a height, length and width of 1cm has a surface area of 6cm squared and a Volume of 1cm cubed. It’s ratio is 6:1
The cubes surface area is six times it’s Volume, whereas the hippos SA is twice it’s Volume. Therefore the cube has a larger SA compared to its V
62
Single called organisms with SA and V
Gases and dissolved substances can diffuse directly into and out the cel membrane. The organisms have a large surface area compared to Volume therefore enough substances can be exchanged across the membrane to supply all the volume.
63
Multi-cellular organisms
They have a smaller SA compared to its volume, therefore not enough substances can diffuse into the organism to supply the large volume. Therefore exchange surfaces are needed for efficient diffusion. Exchange surfaces have to allow enough needed substances to diffuse through. E.g thin membrane for a shorter diffusion distance. Large surface area so lots of substances can diffuse at once.
In animals, lots of blood vessels to get stuff in and out blood fast. Also ventilated so air moves in and out quickly
64
Exchanging substances in leaves
The structure of leaves let gases diffuse efficiently, in and out.
Carbon dioxide diffuse into air spaces in the leaf, then diffuse into cells where photosynthesis happens.
Underneath leaf is an exchange surface - holes called stomata where carbon dioxide can diffuse. Stomata are controlled by guard cells(close if too much water lost etc)
Flattened leaf shape increases surface area.
