B2 Flashcards
1
Q
What are the features of an animal cell?
A
Cell Membrane Nucleus Cytoplasm Ribosomes Mitochondria
2
Q
What are the extra features that plant cells have?
A
Cell Wall
Chloroplasts
Vacuole
3
Q
What is the job of the Nucleus?
A
Contains the genetic information to control the activities of the cell
4
Q
What is the job of the Cytoplasm?
A
Where all of the chemical reactions happen
5
Q
What is the job of the Cell Membrane?
A
Controls what goes in and out
6
Q
What is the job of the Mitochondria?
A
Releasing energy through respiration
7
Q
What is the job of the Ribosomes?
A
Where protein synthesis takes place
8
Q
What is the job of the Cell wall?
A
Gives the cell strength
9
Q
What is the job of the Chloroplasts?
A
The sight of photosynthesis
Makes the plant green (green pigment)
10
Q
What is the job of the Vacuole?
A
Where cell sap is stored
11
Q
What is a yeast cell?
A
A fungus
A single-celled organism
12
Q
What are the features of a yeast cell?
A
Cell wall
Cell Membrane
Cytoplasm
Nucleus
13
Q
What is a bacterial cell?
A
A single-celled organism
14
Q
What are the features of a bacterial cell?
A
Cell wall
Cytoplasm
Cell Membrane
Genetic material
15
Q
What is diffusion?
A
The random spreading out of particles from an area of high concentration to an area of low concentration.
16
Q
Where does diffusion happen?
A
Solutions
Gasses
17
Q
The bigger the difference in concentration, the ______ the diffusion rate.
A
Faster
18
Q
How do dissolved substances move in and out of a plant?
A
By diffusion
19
Q
What can diffuse through a plants cell membrane?
A
Oxygen (respiration)
Glucose
Amino acids
Water
20
Q
How have palisade leaf cells adapted for photosynthesis?
A
Lots of chlorplasts
More chloroplasts at the top- nearer light
Tall shape- big surface area exposed for absorbing CO2
Thin shape- To pack lots at the top of a leaf
21
Q
How have guard cells adapted?
A
Kidney shape- which opens and closes the stomata (pores)
The guard cell goes plump and turgid when filled with lots of water- Stomata opens so gases are exchanged for photosynthesis.
Lose water and become flaccid- when plant is short of water- Stomata closes so water vapour doesn’t escape.
Thin outer walls and thickened inner walls- So the opening and closing works.
Sensitive to light, Close at night- to save water without losing out on photosynthesis.
22
Q
What are guard cells for?
A
Allowing gas exchange
Controlling water loss
23
Q
What are red blood cells a concave shape?
A
To give it a big surface area for absorbing oxygen
So they can pass smoothly through the capillaries
24
Q
What is haemoglobin for in red blood cells?
A
Absorbing oxygen
25
Do red blood cells have a nucleus?
No
26
What are sperm and egg cells?
Specialist cells for reproduction
27
What are the main functions of an egg cell?
Carry female DNA
| Nourish the developing embryo in the early stages
28
What happens when a sperm fuses with an egg?
The eggs membrane changes its structure- stops other sperm getting in so the offspring has the right amount of DNA
29
What is the function of a sperm cell?
to get the male DNA to the female DNA
30
What are the features of a sperm cell?
Long tail and streamlined head to help it swim
| Mitochondria to provide the energy needed
31
Why do sperm carry enzymes in their heads?
To digest through the egg cell membrane
32
What is the process in which cells become specialised for a particular job?
Differentiation
33
What are large multi cellular organisms?
Organisms made up of organ systems
34
When does differentiation occur?
During the development of a multicellular organism
35
What do a group of specialist cells form?
Tissues
36
What does a group of tissues form?
Organs
37
What do a group of organs form?
Organ systems
38
What is a tissue?
A group of similar cells that work together to carry out a paritculair function
39
What are some tissues in the human body?
Muscular
Glandular
Epithelial
40
What do muscle tissues do?
Contract to move what it is attached to e.g the arm
41
What is the job of glandular tissues?
To make and secrete chemicals such as enzymes and hormones
42
What is the job of epithielial tissues?
Covers some parts of the body e.g. the inside of the gut
43
What is an organ?
A group of different tissues that work together to perform a certain function
44
the stomach is and organ made up of what tissues?
Muscular
Glandular
Epithelial
45
What is the job of the muscular tissue in the stomach?
Moves the stomach wall to churn up food
46
What is the job of the glandular tissue in the stomach?
Makes digestive juices to digest food
47
What is the job of the epithelial tissue in the stomach?
Covers the outside and inside of the stomach
48
What is an organ system?
A group organs working together to perform a particular function
49
One example of an organ system
Digestive system- Breaks down food
50
What is the digestive system made up of?
```
Glands
The Stomach
The liver
The Small intestine
The Large intestine
```
51
What are the organs that make up a plant?
Stem
Roots
Leaves
52
What happens in the mesophyll tissue?
Photosynthesis
53
What is the job of the xylem and phloem?
They transport water, mineral ions and sucrose around the plant
54
What is the job of the Epidermal tissue?
Covers the whole plant
55
What is the job of the roots?
Anchor the plant into the ground so it doesn't fall over
Absorb water and mineral ions from the soil
56
What is the job of the stem?
Transports water, mineral ions and nutrients around the plant
Holds up the flowers for reproduction and the leaves towards light
57
What is the job of the leaves?
To take in light needed for photosynthesis
58
What is photosynthesis?
A chemical reaction plants use to make glucose (food) using sunlight
59
What is the equation for photosynthesis?
Light
Carbon Dioxide + Water ----------------> Glucose + Oxygen
Chlorophyll
60
Where does photosynthesis occur?
In the chloroplasts
61
Why do chloroplasts contain chlorophyll?
Absorbs sunlight
| Uses its energy to Carbon dioxide and water into glucose
62
What is the by-product of photosynthesis?
Oxygen
63
What factors effect the rate of photosynthesis?
Light intensity
The volume of CO2
Temperature
64
What is a limiting factor?
Something that stops photosynthesis from happening
65
What does light provide for photosynthesis?
Energy
66
How can you artificially create the ideal conditions for farming?
Using a greenhouse
67
How do plants use glucose?
```
Respiration
Make cell walls
Making proteins
Store in seeds
Store as starch
```
68
What is cellulose?
A substance converted from glucose to make cell walls
69
What are lipids?
Fats and oils stored in seeds.
70
What is the independent variable?
The thing you change
71
What is the dependent variable?
The thing you measure
72
What is the control variable?
The variable you keep the same
73
What affects the population of plants?
Temperature
Availability of nutrients
Water CO2
Amount of light
74
What is the distribution of organisms?
How members of a population are spread out
75
Why are plants randomly distributed in their habitat?
To avoid competition for resources
76
What is a quadrat?
A square grid with an area of one square metre
77
How do you use a quadrat?
Place it in an area
| Count the numbers of different species
78
What is the job of enzymes?
Build up and break down proteins
79
What is a catalyst?
A substance that speeds up the rate of a chemical reaction without being used up
80
What is an enzyme?
A biological catalyst
| A protein that speeds up a reaction
81
What is a protein?
A long chain of amino acids that coils into a ball shape
82
What are proteins used for?
Antibodies
Heamoglobin
Enzymes
83
One way a protein can become denatured
If the temperature becomes too hot
84
What is a substrate?
A chemical that an enzyme can work on
85
What do digestive enzymes do?
Break down large molecules into smaller molecules e.g. Starch into Glucose
86
What does Amylase do?
Breaks down starch into sugar
87
What does Protease do?
Breaks doen protein into amino acids
88
What does Lipase do?
Breaks down fat into glycerol and fatty acid
89
What is the job of hydrochloric acid in the stomach?
Kills bacteria on food
| provides the right conditions for digestive enzymes
90
What is the job of bile salts in the stomach?
Break down or emulsifies fats
91
What is denaturation?
When an enzyme changes shape and the active site can no longer fit a substrate.
92
Why are enzymes used in washing powder?
To kill bacteria on clothes
93
Why are enzymes used in baby foods?
To break down proteins (proteases)
94
What is the equation for respiration?
Glucose + Oxygen = Carbon dioxide + Water + energy
95
What is respiration?
The process which releases energy from glucose.
96
What is the equation for anaerobic respiration?
Glucose = Lactic acid + energy
97
What does lactic acid do?
Cause your muscles to become fatigued
98
What does anaerobic mean?
A chemical reaction without oxygen
99
What is oxygen dept?
When your body uses oxygen to convert lactic acid back into glucose
100
What is mitosis?
When cells divide to replicate themselves and make an exact copy of their DNA
101
What type of cells divide using mitosis?
Normal, somatic cells
102
Why do cells divide by mitosis?
Growth
Repair
Replacing damaged cells
103
What are gametes?
A gamete is a sex cell
Sperm + egg
Pollen + Ovules
104
How are gametes made?
They are made during meiosis
105
How much DNA does a gamete hold?
Half the DNA
23 pairs
(Haploid- n)
106
What is a zygote?
A diploid- 2n
107
How much DNA does a zygote hold?
Two sets of chromosomes
| 46 pairs
108
What type of cell divides by mitosis?
Bacteria- Asexual reproduction
109
What is chaismata?
The crossover / sharing of genes/ DNA- Variation
110
What is Cystic Fibrosis?
A genetic disease that is caused by a recessive faulty gene
111
What are the effects of Cystic Fibrosis?
Too much mucus in the lungs, unless removed can lead to chest infections.
112
What type of disease is Polydactyly?
Dominant
113
What is embryonic screening used for?
Identifying inherited diseases e.g. Cancer, Cystic Fibrosis
| Identify % risks of disease
114
What is DNA fingerprinting used for?
Identifying + linking suspects to DNA evidence
| Profiling
115
How is a fossil formed?
Organism dies- falls to the bottom of the sea
Sediment falls on top- forming layers
More and more layers form after millions of years
Bones are replaced by minerals
Minerals harden- form and imprint
Fossil is formed
116
What does extinction mean?
When all of a species dies and has a population of 0
117
Some examples of extinct animals
Wooly mammoth
Dodo
Dinosaurs
Sabre tooth tiger
118
What does endangered mean?
When a species is in danger of becoming extinct.
119
What causes extinction?
```
Natural competition
Predators
Disease
Changes to environment
Natural Disasters
```
120
What are chromosomes?
Long molecules of DNA
121
What are genes?
A section od DNA
122
Which cells can turn into any type of cell?
Embryonic stem cells
123
How can stem cells be used?
Bone marrow transplants
| Replace faulty cells
124
What are some reasons people are against stem cell research?
The embryos are all potential life
| The feel that doctors should concentrate on developing other sources of stem cells
125
Which chromosomes do men have?
X + Y
126
Which chromosomes do women have?
X + X
127
What is the probability that a baby will be a boy?
50:50
| 50%
128
What is the probability that a baby will be a girl?
50:50
| 50%
129
Who way Gregor Mendel?
The founder of genetics
130
What were the three conclusions Mendel reached?
The characteristics of plants were determined by genes
Genes are passed on from both parents, one from each parent
Genes can be dominant or recessive
131
What are alleles?
Different versions of the same gene
132
Describe HOMOZYGOUS
When an organism has two of the same alleles of a gene
133
Describe HETEROZYGOUS
hen an organism has two different alleles of a gene
134
A dominant allele is shown with a ______ letter.
Capital
135
A recessive allele is shown with a _____ letter.
Small
136
What type of allele causes Cystic fibrosis?
A recessive allele- f
137
What would a person with Ff allele be called?
A carrier
138
Does someone with the ff allele have Cystic fibrosis?
Yes
139
What type of allele causes Polydactyly?
Dominant- D
140
Will the person with a Dd allele suffer with Polydactyly?
Yes
141
What is embryo screening?
When cells from the embryos that will be used in IVF are removed to analyse their genes to detect any genetic disorders
The good alleles will be implanted into the womb
142
What are some of the arguments against embryo screening?
The 'bad' embryos are destroyed- they could have developed into humans
It implies people with genetic problems are undesirable
Screening is expensive
143
What are some of the arguments for embryo screening?
It will help to stop people suffering
There are laws to stop it being used for the wrong reasons e.g. selecting the sex of a baby
Screening allows the selected embryo to be healthy
144
What is speciation?
The development of a new species
145
What is isolation?
when populations of a species become separated
146
What can cause speciation?
Isolation
| Natural selection
147
Why does speciation occur?
Because populations become so different they can no longer breed to produce fertile offspring
