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Biology > SB1 - Key Concepts > Flashcards

SB1 - Key Concepts Flashcards

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1
Q

What is magnification

A

If makes an image look bigger

So a x30 lens would make an object 30 times bigger

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2
Q

How do you work out a microscopes magnification

A

Multiply the magnification of the 2 lenses together

Multiply the eyepiece lens and objective lens

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3
Q

What’s the resolution

A

The smallest distance between two points that can still be seen as 2 seperate points

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4
Q

What are electron microscopes like

A

Instead of light beams passing through the specimen to build up an image

Electron Microscopes can magnify more and have a better resolution than a light microscope

They allow us to see cells with great detail and clarity

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5
Q

Tell me the prefixes

A

Millimetres (mm)
Micrometres (um)
Nanometres (nm)
Picometres (pm)

Divide by 1000 to to get down a stage eg mm to um

Multiply by 1000 to get up a stage eg micro to milli

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6
Q

What is a cell with a nucleus also described as

A

Eukaryotic

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7
Q

What is the cell membrane

A

Is like a very big thin bag

It controls what enters and leaves the cell and seperates one cell from another

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8
Q

What’s the cytoplasm

A

It contains a watery jelly and it’s where most cells activities happen

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9
Q

What are mitochondria

A

Are jelly bean shaped structures in which aerobic respiration

Very difficult to see with a light microscope

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10
Q

What’s the nucleus

A

Controls the cell and its activities

Inside it are chromosomes which contain DNA

Especially large in white blood cells

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11
Q

What are ribosomes

A

In cytoplasm many round tiny structures make proteins for cell

Impossible to see with light microscope

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12
Q

What is the field of view

A

The circular area you see in a light microscope

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13
Q

What do electron microscopes allow us to see that light microscopes can’t

A

Mitochondria

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14
Q

What’s the cell wall

A

In a plant cell

It’s made of cellulose and supports and protects the cell

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15
Q

What are chloroplasts

A

In plant cell

Contain chlorophyll which traps energy transferred from the sun

The energy is used for photosynthesis

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16
Q

What’s a vacuole

A

In plant cells

Stores cell sap to help cell keep firm and rigid

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17
Q

What are specialised cells

A

They have a sledie if function

About 200 different kinds

They are adapted to their functions

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18
Q

How are the cells adapted in the small intestine lining specialised

A

They absorb small food molecules produced by digestion

Adapted by having membranes with tiny folds called microvilli

This adaption increase the surface area of the so more molecules can be absorbed, the faster the absorption Happens

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19
Q

How is the pancreas adapted

A

It makes enzymes needed to digest certain foods in the small intestine

Enzymes are proteins and so these cells are adapted by having a lot of ribosomes

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20
Q

What are gametes

A

In sexual reproduction, the two specialised cells sex cells, they fuse to create a cell that develops into an embryo

Human gametes are egg cell and the sperm cell

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21
Q

How many chromosomes do most body cells have

A

Two copies of the 23 different type of chromosome so 46 in total

Gametes one have one copy of each and so 23 each

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22
Q

What are cells with two sets of chromosomes also known as

A

Diploid

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23
Q

What are cells with one copy of each chromosomes called

A

Haploid

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24
Q

How is the female egg cell gamete specialised

A

The jelly coat protects egg cell, it hardens after fertilisation to ensure that only one sperm enters the egg cell

The cytoplasm is packed with nutrients to supply the fertilised egg cell with energy and material for the growth and development of embryo

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25
How is the male sperm cell specialised
It has a streamlined shape to travel It has a large number of mitochondria are arranged in a spiral around the top of the tell to release lots of energy to power the tail The tip of the head contains a small Vacuole called the acrosome - it contains the enzymes that break down substances in the eggs cells jelly coat Allows sperm to Burrow inside
26
What happens in fertilisation
Occurs in the oviducts, cells in the lining of oviduct transport cells (or the developing embryos after fertilisation) towards uterus
27
How are oviduct cells adapted
Have hair like cilia - wave side to side to sweep substances along
28
What are cells that kind structures in the body also called
Epithelial cells
29
What are cells that line structures in the body and have cilia also called
Ciliated epithelial cell
30
How do we look at bacteria
Difficult to see with light microscopes as small and colourless so stains often used
31
What is the flagellum on a bacteria
A round like propeller so the bacteria can move Not all bacteria have them
32
What type of cells are bacteria
Prokaryotic Cells don't have nuclei or chromosomes Don't have mitochondria or chloroplasts
33
Instead of a nucleus what does a bacteria contain
One large loop of chromosomal DNA - also smaller loops of DNA called plasmids
34
What do Plasmids do
Controls a few of the cells activities
35
Tell me some parts of the bacteria cell
Slime coat for protection (not all bacteria have this) Flexible cell wall for support which is not made out of cellulose like plants Cell membrane Cytoplasm, contains ribosomes which are smaller than eukaryotic ribosomes Chromosomal DNA
36
How big is prokaryotic ribosomes
20nm
37
How many Nanometres In a metre
1 000 000 000nm
38
You need to know standard form
Check page 11 of text book for info
39
What do animals use substances for
Energy, growth, development by digesting food inside their bodies
40
How do bacteria use substances
Release digestive enzymes into environment and then abstain digested good into their cells
41
What do digestive enzymes turn in to in humans
Large molecules in our food into smaller smaller subunits The digested molecules are them small enough to be absorbed by small intestine
42
What do part of protein molecules breakdown to
Amino acids
43
What do part of starch molecules break down into
Glucose molecules
44
What do lipid molecules break down to
Fatty acids
45
What's synthesis
Using small molecules to build larger molecules Carbohydrates and proteins are both polymers because they are made of I small molecules or monomers joined in a chain Happens very slowly - since subunits rarely collide with enough force or right angle to bond
46
How can synthesis or breakdown (digestion) be sped up
Using a catalyst and in living organisms they are enzymes Enzymes are biological catalysts - enzymes are a special group of proteins found throughout the body
47
What are the substances that that enzymes work on called
Substrates
48
What are the substances produced when a catalyst reacts with a substrate called
Products
49
Tell me about the enzyme amylase
Found in saliva and small intestine It breaks down starch to small sugars such as maltose
50
Tell me about catalase
Found in most cells, especially liver cells Breaking down hydrogen peroxide made in many cell reactions to water and oxygen
51
Tell me about starch synthase enzyme
Found in plants It used for synthesis of starch from glucose
52
Tell me about DNA polymerase enzyme
Found in nucleus Used for synthesis of DNA from its monomers
53
What are chemical reagents
Identify changes in sugars and stuff
54
How can an iodine solution be used for chemical reagents
Changes from yellow-orange to blue-black colour when in contact with starch
55
What can benedicts solution be used for in chemical reagents
Change colour when reducing sugars (including glucose and fructose) are present
56
What can a biuret test be used for
Potassium hydroxide is mixed with a solution of food, 2 drops of copper sulfate solution and changes to purple of protein present
57
How can fats and oils (lipids) be tested
Using ethanol emulsion test Food mixed with ethanol and shaken and poured into water and shaken agian Fats and oils dissolved in ethanol float to surface, forming a cloudy emulsion when left to stand
58
What do calorimeters do
The amount of energy transferred from biting food to water can be calculated from increase in water temperature Measures amount of energy in a food by burning it
59
How is a protein formed
Formed from a chain of amino acids, caused by folding the chain in a sequence of specific amino acids in a chain
60
What's the active site
Where the substrate molecule of the enzyme fits at the start of a reaction Different substrates have different 3D shapes and different enzymes have different shaped active sites Enzymes can only work with specific substrates
61
Tell me what happens when substrate molecule enters an enzymes active site
Two different substrate molecules hold the substrate molecules tightly in right position for bonds to form between them and make 1 product molecule
62
What can the ph or temperature change do to an enzyme
It can affect how the proteins fold up and affect the shape of active site If the shape of the active site changes too much, the substrate will no longer fit neatly and so the enzyme will no longer catalyse We say the enzyme is denatured
63
What's the temperature at which the enzyme works fastest also Known as
Optimum temperature
64
What else beside temperature can affect the rate of an enzymes reaction
Ph - below and above optimum the shape of the active site is changed concentration of substrate - high concentration most enzymes active sites contain substrate molecules so it's as fast as it can be At low concentration, many enzyme molecules have Empty active sites so rate very slow
65
How is smell spread
Diffusion
66
Tell me about diffusion
Particles in gases and liquids are constantly moving past eachother in random directions This causes an overall movement of particles from where there are more of them (higher concentration) to where there are fewer (lower concentration)
67
What's a concentration gradient
The difference between 2 concentrations, Particles diffuse down a concentration gradient The bigger the difference, the steeper the gradient and faster diffusion occurs
68
Tell me about diffusion in body
Allows small molecules such as oxygen and carbon dioxide to move in and out of cells
69
What is partially permeable or semi permeable
A membrane that allows some molecules through and not others
70
How do cells do diffusion
Their cell membrane are semi permeable and trap large soluble molecules inside cells, water molecules can diffuse through
71
What's a more dilute solute concentration
When there are more water molecules on one side of cell membrane and Less on other (more concentrated solution of solute)
72
What's osmosis
The diffusion of small molecules of a solvent such as water through a semi permeable membrane The overall movement of solvent particles will stop when the concentration of solutes is the Same on both sides of membrane
73
How do you calculate mass change
Osmosis can cause mass change Work out difference between mass of tissue at start and end (final mass - initial mass) Divide difference by initial mass Multiply by 100 A negative answer is a percentage lost
74
What's active transport
Cells may need to transport molecules against a concentration or transport molecules that are too big to diffuse through the cell membrane
75
How is active transport carried out
By transport proteins in cell membranes The transport proteins capture certain molecules and carry them across the cell membrane Active process requires energy
76
What type of processes are osmosis and diffusion
Passive Do not require an input of energy

Biology (12 decks)

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