U5 biology GCSE Flashcards
1
Q
Multicellular organisms
A
An organism which is made up of many different cell which work together. Some of the cells are specialised for different functions in the organism.
2
Q
Differentiated
A
Specialised for a particular cell
3
Q
Tissue
A
A group of specialised cells all carrying out the same function.
4
Q
Muscular tissue
A
The tissue which makes up the muscles. It can contract and relax.
5
Q
Glandular tissue
A
The tissue which makes up the glands and secretes chemicals, e.g enzymes, hormones
6
Q
Epithetical tissues
A
Tissue made up of relatively unspecialised cells which line tubes and organs of the body.
7
Q
Epidermal tissues
A
The tissue of the epidermis the outer layer of the organism
8
Q
Mesophyll tissue
A
The tissue in a green plant where photosynthesis takes place
9
Q
Xylem tissue
A
The non living transport tissue in plants which transports water around the plant
10
Q
Phloem tissue
A
The living transports in plants which carries sugars around the plant
11
Q
Digestive juices
A
The mixture of enzymes and other chemicals produced by the digestive system
12
Q
Organ systems
A
A group of organs Working together to carry out particular functions
13
Q
Small intestine
A
The region of the digestive system where most of the digestion of food takes place
14
Q
Kidney tubules
A
A structure in the kidney where substances are reabsorbed back into the blood
15
Q
Mitochondria
A
Where energy is released during aerobic respiration
16
Q
Ribosomes
A
Where protein synthesis takes place
17
Q
Diffusion
A
Is the spreading out of the particles of a fluid
18
Q
Net movement
A
The net movement into or out of cells depends on the concentration of the particles on each side of the cell membrane
19
Q
What is the concentration gradient
A
The difference between the area of high concentration and low concentration
The larger the difference in concentration the faster the rate of diffusion
20
Q
Examples of diffusion
A
Diffusion of oxygen into the cells of the body from the bloodstream as the cells respire
Diffusion of carbon dioxide into a photosynthesising plant
21
Q
The digestive system
A
Glands: pancreas and salivary glands which produce digestive juices
Stomach where digestion occurs
Liver which produces bile
Gall bladder: stores and releases bile
Small intestine absorption of soluble food occurs
Large intestine where water is absorbed.
22
Q
Equation for photosynthesis
A
Light energy
Carbon dioxide+water——– glucose+oxygen
Chlorophyll
23
Q
What are the three important limiting factors in photosynthesis
A
Light
Carbon dioxide concentration
Temperature
24
Q
How may the glucose produced by photosynthesis be used
A
Converted into insoluble starch
Used for respiration
Converted into fats and oils for storage
Used to produce cellulose which strengthens cell walls
Used to produce protein (with nitrate ions)
25
Most human and animal cells have the following parts
A nucleus, controls cell activities
Cytoplasm, where chemical reactions take place
Cell membrane, controls the passage of substances into and out of the cell
26
Plant and algal cells also have a cell wall made of cellulose. Plant cells often have
Chloroplasts
| A permanent vacuole
27
Bacterial cell consists of
Cytoplasm and a membrane surrounded by a cell wall
28
Yeast is a single called organism they have
A nucleus, cytoplasm, and membrane surrounded by a cell wall
29
Cells may be specialised
To carry out a particular function
30
Dissolved substances can
Move into and out of cells by diffusion
31
What is the equation for photosynthesis
Light energy
| Carbon dioxide+ water---------------glucose+ oxygen
32
What does the iodine test show
By testing leaves with iodine solution we can identify the starch in the leaf and show that photosynthesis has occurred. Variegated leaves have patches of green (chlorophyll) and white (without chlorophyll) only green patches will turn the iodine solution blue-black to show that starch has been made
33
Name the three most common limiting factors and describe their limitations
Light- a lack of light slows down the process of photosynthesis
Temperature- if it is too cold the enzymes do not work effectively and slow down photosynthesis
Carbon dioxide- if there is too little carbon dioxide then the rate of photosynthesis will slow down
34
What is an independent variable
It is the one being tested
35
What is a dependent variable
The one that you measure
36
What are the uses of soluble glucose
Converted into insoluble starch for storage
Used for respiration
Converted into fats and oils for storage
Used to produce cellulose which strengthens cell walls
Used to produce proteins
37
What do plant and algal need a supply of
Mineral ions such as nitrate ions in order to produce protein
38
Protein molecules are made of
Long chains of amino acids
39
Proteins can be
Muscle
Hormones
Antibodies
Catalyst
40
Chemical reactions in cells are controlled by
Proteins called enzymes
41
Enzymes are biological catalysts meaning
They speed up chemical reactions
42
Enzymes are large proteins and the shape of the enzyme is vital as
The shape has an area where other molecules can fit, this is called the active site
43
The substrate is
The substrate in a reaction can be held in the active site and either be connected to another molecule or be broken down
44
Enzymes can
Build large molecules from many smaller ones
Change one molecule into another one
Break down large molecules into smaller ones
45
Reactions take place faster when it is warmer as
Higher temperatures the molecules move around move more quickly and so collide with each other more often and with more energy
46
If the temperature gets too hot
The enzymes stops working because the active site changes shape. This means the enzymes becomes denatured
47
Each enzyme works best at a
Particular pH value, some work best in acid conditions but others need neutral or alkaline conditions
48
Amylase
A carbohydrase is produced by the salivary glands, the pancreas and small intestine. Amylase catalyses the digestion of starch into sugars in the mouth and small intestine
49
Protease
Is produced by the stomach, the pancreas and the small intestine. Protease catalyses the breakdown of proteins into amino acids in the stomach and small intestine
50
Lipase
Is produced by the pancreas and small intestine. Lipase catalyses the breakdown of lipids, fats and oils, to fatty acids and glycerol
51
The liver produces
Bile that is stored in the gall bladder. The alkaline is squirted into the small intestine and neutralises the stomach acid. Bile makes the conditions in the small intestine slightly alkaline
52
What do biological detergents contain
Proteases and lipase that digest. They work at
53
Biological detergents contain
Pot eases and lipase that digest food stains. They work at lower temperatures than ordinary washing powders which saves energy and money spent on electricity
54
Proteases are used in industry to
Make baby foods by pre-digesting the
55
Isomerase is used to
Convert starch into sugar syrup for use in foods
56
What are the advantages of using enzymes
Enzymes in biological washing powders are very effective at removing stains such as blood, grass and gravy
Biological washing powders can be used at lower temperatures this saves energy and reduces costs
Some enzymes are used in medicine to diagnose disease
57
Disadvantages of using enzymes
If people misuse washing powders they may have allergic reactions
Enzymes may enter water ways via the sewage system
Industrial enzymes can be costly to produce
Enzymes denature at high temperatures needed to kill pathogens in the washing
Fabrics such as wool will be digested by proteases
58
Where does respiration take place
In the mitochondria
59
What is the equation for aerobic respiration
Glucose+ oxygen--------- carbon dioxide+water+energy
60
Energy released may be used by the organism to
Build larger molecules from smaller ones
Enable muscle contraction in animals
Maintain a constant body temperature
Build sugars, nitrates and other nutrients into amino acids
61
Why do you need to increase the rate at which oxygen and glucose reach the muscle cells for aerobic respiration
As you need to remove the extra waste carbon dioxide produced more quickly as well as allowing the heart rate to increase and supply more blood containing oxygen and glucose to reach the muscles
62
What does glycogen do
It can be converted back to glucose for use during exercise
63
What happens in anaerobic respiration
The glucose is not completely broken down in anaerobic respiration and lactic acid is produced. The less energy that is released from the glucose in anaerobic respiration. The build up of lactic acid causes muscle fatigue and blood flowing through the muscles will remove the lactic acid
64
What is the extra oxygen that is needed to break down lactic acid called
Your oxygen debt
65
What is mitosis
Mitosis is the result of two identical cells being produced form the original cell. The chromosomes contain the genes(alleles) which must be passed on to each new cell. A copy of the chromosomes are made before the cell divides and each one of the chromosomes goes to each new cell.
66
How do gametes divide
Meiosis
67
Sexual reproduction results in
Variation as the gametes from each new parent fuse when the gametes join at fertilisation a single body cell with new pairs of chromosomes is formed
68
Describe meiosis
Before dividin a copy of each chromosome is made
The cell now divides twice to form four gametes
Each gamete has a single set of chromosomes each with a different combination of genes
69
What are stem cells
Stem cells are unspecialised
Stem cells are found in the human embryo and in adult bone marrow
Stem cells change into all the different types of body cell (differentiated)
Layers of cells in the embryo differentiate
70
Who was Mendel
He was a monk who worked out how characteristics were inherited
Scientists at this time did not know about chromosomes or genes
71
What are chromosomes and genes
Chromosomes are made out of DNA which is a very long molecule with a double helix structure
Genes are short sections of DNA
72
Genes controlling the same characteristics are
Alleles
73
If an allele masks the effect of something it is
| If an allele is masked by something it is
Dominant
| Recessive
74
Phenotype
Physical appearance of the characteristic
75
Genotype
The genetic make up, which allele does the individual inherit
76
Homozygous is when
| Heterozygous is when
Both alleles are the same
| The two alleles are different
77
What is polydactyl
When babies are born with extra fingers or toes
Polydactyl is caused by a dominant allele
It can be inherited from one parent who has the condition.
78
What is cystic fibrosis
Organs become clogged by thick mucus causing respiratory and reproductive problems
There is no cure most have a life span of 30
It is caused by a recessive allele so it must be inherited from both parents, parents will be carriers
79
What are the arguments in favour of using embryonic stem cells
Offer one of the best chances if finding treatments for paralysis spinal injury Alzheimer's and diabetes
Embryos used are usually spare embryos from infertility treatment which would be destroyed anyway
Embryos being created from adult cells for use in research, they would never become babies
Could be used to grow new tissues and organs for transplants
80
Arguments against using embryonic stem cells in research
Very experimental and there is a risk that they may cause further problems such as the development of cancers
All embryos have the potential to become babies, therefore it is wrong to experiment
Embryos cannot give permission to be used in experiments
It takes a long time to develop any therapy time would be better spent on other possible treatments such as new drugs or using adult stem cells
81
What are the ethical issues of screening
People in affected families can take the test and use it to decide whether or not they want the baby.
Embryos can be tested during pregnancy and may decide to abort the baby depending on the results
Some will have the embryos screened before the embryos are implanted in the women to see if they have genetic disorders
82
How does sexual reproduction give rise to variation
As when gametes fuse one of each pair of alleles comes from each parent
83
What are characteristics controlled by
They ses controlled by a single gene, each gene may have different forms called alleles
84
What is an allele
An allele controls the development of a characteristic when it is present on only one of the chromosomes is a dominant allele, as well as this an allele that controls the development of characteristics only if the dominant allele is present is a recessive allele
85
How is each gene coded
It is coded for a particular combination of amino acids which makes a specific protein
86
What are fossils
Evidence for early forms of life come from fossils,
Fossils are the remains of organisms from many years ago they are found in rocks and are formed in various ways
The hard parts of animals that do not decay, the parts of organisms that have not decayed because one or more of the conditions needed for decay are absent, when pats of the organism are replaced by other materials as they decay, as preserved traces of organisms such as footprints and burrows
87
Why do we not have evidence for all life forms
Many early life forms were soft bodied which means that they left fre traces behind
88
How is extinction caused
Changes to the environment over geological time
New predators
New diseases
New competitors
A single catastrophic event e.g. Volcano/ asteroid
Through the cyclical nature of speciation
89
New species arise as a result of
Isolation- two populations of a species become separated
Genetic variation- each population has a wide range of alleles that control their characteristics
Natural selection- in each population the alleles that control the characteristics which help the organism to survive are selected
Speciation- the population become so different that successful interbreeding is no longer possible
