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Biology > B1 > Flashcards

B1 Flashcards

(85 cards)

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1
Q

What are eukaryotic cells

A

They are complex and include all animal and plant cells

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2
Q

What are prokaryotic cells

A

Small and simpler cells e.g bacteria

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3
Q

Name the five subcellular structures of an animal cell

A

Nucleus, cytoplasm, cell membrane, mitochondria and ribosomes

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4
Q

Define the nucleus

A

Contains genetic material that controls the activities of the cell

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5
Q

Define cytoplasm

A

Gel-like substance where chemical reactions happen. It also contains enzymes to control the chemical reactions

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6
Q

Define cell membrane

A

Holds cell together and controls what goes in and out of

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7
Q

Define mitochondria

A

Reactions for aerobic respiration take place here and transfers energy that cell needs

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8
Q

Define ribosomes

A

Where proteins are made in the cell

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9
Q

Name the three things that a plant cell has that animal cells don’t

A

Cell wall, permanent vacuole, chloroplasts

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10
Q

Define cell wall

A

Made of cellulose and supports and strengthens cell

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11
Q

Define permanent vacuole

A

Contains cell sap

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12
Q

Define chloroplasts

A

Where photosynthesis occurs which makes food for the plant. They contain chlorophyll which absorbs light

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13
Q

Name subcellular structures of bacterial cells

A

Cytoplasm, cell membrane, cell wall, a singular strand of DNA(acts as a nucleus and floats freely in cytoplasm) and plasmids (small rings of DNA)

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14
Q

What do bacterial cells not have

A

Chloroplasts, mitochondria and a true nucleus

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15
Q

Light microscope

A

Uses light and lenses to magnify
Shows individual cells and larger sub cellular structure (nucleus)

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16
Q

Electron microscopes

A

Uses electrons
Higher magnification
Higher resolution - see smaller things in more detail (internal structures of mitochondria)

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17
Q

What is the formula for magnification

A

Image size = magnification x real size

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18
Q

Conversions from cm - mm - micrometers(um) - nanometres(nm)

A

X10
X1000
X1000

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19
Q

How do you prepare a slide

A

1) drop of water in middle of clean slate
2)cut up onion and separate into layers
3) use tweezer to place one layer on slide
4)add drop of iodine solution this highlights the object
5)place cover slip on top - try not to get air bubbles

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20
Q

How do you use a light microscope

A

1) clip slide on stage
2) put on lowest powered objective lens
3)use coarse adjustment knob to move stage just below lens
4) look in eyepiece and move stage downwards until roughly in focus
5) adjust focus with fine adjustment knob until clear
6) if need greater magnification - swap to higher powered lens and refocus

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21
Q

Define differentiation

A

Process by which a cell changes to become specialised for its job

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22
Q

When is an animal cell able to differentiate

A

At a early stage as they aren’t specialised yet

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23
Q

When is a plant cell able to become specialised

A

Always

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24
Q

Why do cells differentiate in mature animals

A

For repair and replacing cells

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25
What are undifferentiated cells called
Stem cells
26
What are sperm cells for
Reproduction
27
Function of sperm cell
To get male DNA to female DNA
28
How has the sperm cell adapted to help it swim to the egg
Long tail, streamlined head, lots of mitochondria to provide energy, carries enzymes in its head to digest through egg cell membrane
29
What are nerve cells specialised for
Rapid signalling
30
What is the function of nerve cells
To carry electrical signals from different parts of the body
31
How are nerve cells adapted
Long (to cover more distance), branched connections at ends to connect to other nerve cells to make a network throughout the body
32
What are muscle cells specialised for
Contraction
33
What is the function of muscle cells
To contract quickly
34
How are muscle cells adapted
Long so they have space to contract, contain lots of mitochondria to generate energy needed for contraction
35
What are root hair cells specialised for
Absorbing water and minerals
36
How are root hair cells adapted
On surface of plant roots and stick out into the soil for a big surface area for absorbing water and mineral ions from the soil
37
What are phloem and xylem cells specialised for
Transporting substances
38
What do phloem and xylem cells form
Tubes
39
What do phloem and xylem tubes transport around the plant
Food and water
40
Why are xylem cells hollow
So stuff can flow through them
41
Why do phloem cells have few subcellular structures
So stuff can flow through them
42
Define chromosomes
Coiled up lengths of DNA molecules
43
Where are chromosomes found
In the nucleus
44
What do chromosomes carry
Large number of genes
45
What are genes
They define the development of different characteristics e.g. hair colour
46
How many pairs of chromosomes are there in each cell
There are 23 pairs (46 chromosomes altogether) in each pair one is from the father and one from the mother
47
What is the process of when the cell divides called
Mitosis
48
Why do multicellular organisms use mitosis
To grow or replace cells that have damaged
49
What happens in growth and DNA replication
1) DNA is spread out in long strings 2)cell grows and increases subcellular structures e.g. mitochondria and ribosomes 3)it duplicates its DNA and forms X-shaped chromosomes (46 pairs)
50
What happens during mitosis
1) Chromosomes line up at centre and are pulled apart and they go to opposite ends of the cell 2) membranes form around each of the sets of chromosomes (nucleus) 3)the cytoplasm and cell membrane divides 4)splits into two identical cells
51
Where are stem cells found
Human embryos, bone marrow(can only turn into blood cells)
52
What are stem cells used for
Medicines and research
53
What are the risks for using stem cells in medicine
Stem cells from lab could be contaminated with virus and passed to patient
54
How are bone marrow stem cells used to cure disease
They can replace faulty blood cells
55
Why are people against stem cell research
They embryo has a potential human life
56
Where are stem cells found in the plant
Meristems where growth occurs
57
What can stem cells from plants do
Produce clones for whole plants quickly and cheaply, grow plants of a rare species, grow crops of identical plants that’s have desired features for farmers (disease resistant)
58
Define diffusion
It is the net movement of particles from a high concentration to a low concentration until evenly spread
59
What happens when the concentration gradient is bigger
The rate of diffusion is faster
60
How does a higher temperature give a faster diffusion rate
The particles have more energy so move around faster
61
How do dissolved substances move in and out of cells
Diffusion
62
Why can’t starch and proteins fit through a membrane
The particles are too big to diffuse
63
What molecules can diffuse through a membrane and why
Oxygen, glucose, amino acids and water because they are small
64
What does a larger surface area of the membrane cause
A faster diffusion rate because more particles can pass through at once
65
How are embryonic cells used to cure diseases
They replace faulty cells in sick people
66
Therapeutic cloning
Embryo made to have the same genetics as the patient so the stem cells produced aren’t rejected
67
arguments for stem cell research
Curing existing patients is more important than embryos Use unwanted embryos from fertility clinics which would be destroyed anyway
68
What is osmosis
The net movement of water molecules from a high water concentration to a low water concentration across a partially permeable membrane
69
Define a partially permeable membrane
Membrane with small holes only small molecules can fit
70
How do root hair cells have a large surface area and why
Each branch of root is covered in root hair cells for absorbing more mineral ions (for healthy growth) and water from the soil
71
Why can’t minerals and water diffuse into root hair cells and what is used instead
Because the concentration in root hair cells is higher than the soil so activate transport used instead that goes against the concentration gradient bu needs energy from respiration to do so
72
How is active transport used in humans
In the gut where lower concentration of nutrients in gut and higher in blood To get nutrients into the blood to use for respiration
73
What does the ease of exchanging substances depend on
Surface area of volume ratio Larger organism has a smaller surface area to volume ratio so harder to exchange to provide for cells
74
How do single called organisms exchanges gases
Gas diffuses directly into cell as they have large surface area to volume ratio so enough substances can be exchanged to supply to volume of the cell
75
How do multicellular organisms exchange gases
Small surface are to volume ratio so not enough substances diffuse from outside to supply to the entire volume
76
How do exchange surfaces adapt to maximise effectiveness
Thin membrane - short distance to diffuse Large surface area- lots of substance can diffuse at once Lots of blood vessels on surface - gets stuff into blood quicker Gas exchange surfaces are ventilated - moves air in and out
77
How does alveoli maximise diffusion in gas exchange
Enormous surface area Moist lining for dissolving gases Very thin walls Good blood supply
78
What is villi and what does it do
Inside the small intestines there are lots of villi - a single layer of surface cells Increases surface area so digested food is absorbed quicker into the blood to use Very good blood supply to absorb quickly
79
Gas exchange in a leaf
CO2 diffusés into air gaps in leaf then diffuses quickly into cells to photosynthesise Underneath the leaf is the exchange surface covered in stomata (tiny holes) that the co2 diffuses through O2 and water vapour diffuse out through stomata
80
How are leaf’s adapted for gas exchange
Size of stomata controlled by guard cells to close the stomata if the plant is losing water faster than replaced Flattened leaf shape - increases area of exchange surface Walls fo cell inside leaf form exchange surface Air spaces inside the leaf increase surface area so more chance co2 gets in
81
What are gills
Gas exchange surface in fish
82
Gas exchange in fish
Water enters through mouth and passes through the gills O2 diffuses from water to blood and the co2 diffuses from blood to the water
83
How are fish adapted for gas exchange
Gills made of gill filaments to give large surface area Lamellae are tiny structures covering the gill filaments to increase the surface area Lost of capillaries to speed it up Thin layer of surface cells to minimise distance to diffuse
84
How do fish maintain a larger concentration gradient for diffusion
Blood flows through lamellae in one direction and water in the other The concentration of water always higher in water so lots of 02 diffuses
85
Sugar solutions on plant tissues practical
1) cut up potato into identical cylinders 2)get beakers with different sugar concentrations - pure water and very concentrated(1 mol/dm3) and in between 3)measure mass of cylinders and leave in beakers for 24 hours 4)take out and dry then measure mass again 5)if drawn in water by osmosis the mass increases 6)calculate the change in mass and plot on graph 7)errors - if they aren’t fully dried they’ll have a higher mass, water can evaporate from beakers so changes concentration 8)repeat and calculate mean for each concentration

Biology (5 decks)

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