BIOLOGY Flashcards
1
Q
What does a nucleus do in a cell?
A
It controls the cell’s activities and contains the genetic material for cellular reproduction.
2
Q
What is the function of cytoplasm?
A
It’s where most of the chemical reactions take place in a cell
3
Q
What does the cell membrane do?
A
It controls what comes in and goes out of a cell.
4
Q
What do mitochondria do?
A
Sub-cellular structures where aerobic respiration takes place
5
Q
What do ribosomes do?
A
Ribosomes synthesise proteins
6
Q
What is a cell wall made of?
A
Cell walls are plants’ cells - they are made of cellulose to strengthen the cell.
7
Q
What is the function of chloroplasts?
A
Chloroplasts - found in plant cells - make glucose (food) for the plant through photosynthesis.
8
Q
Name the two main kinds of cell
A
Prokaryotic cells (bacterial) Eukaryotic cells (plant, animal, fungal)
9
Q
What are some of the main differences between prokaryotic and eukaryotic cells?
A
Prokaryotic cells are: Smaller Genetic material is not in a nucleus Genetic material is in a single DNA loop and there may be one or more small rings of DNA called PLASMIDS They do not contain mitochondria or chloroplasts
10
Q
What kind of shapes can bacteria have?
A
Spherical
Spiral
Rod
Curved rod
11
Q
What are flagella?
A
Tails on cells to move them around (e.g. sperm cells or bacteria)
12
Q
Explain the nature of plasmids
A
They are loops of DNA found in bacteria. They can be transferred from one cell to another, allowing bacteria to pass genes around. They are also useful for scientists to insert genes into different bacteria.
13
Q
Define ‘resolution’ in the context of microscopes
A
The ability to discern more than one object - e.g., cells can’t be seen with the naked eye, but under a microscope, they begin to be ‘resolved’.
14
Q
What do electron microscopes do?
A
They pass electrons through a specimen being ‘viewed’ giving a much clearer image.
15
Q
What is the formula for calculating magnification?
A
Magnification = size of image/size of real object
16
Q
What sub cellular structure controls activities in the cell?
A
Nucleus
17
Q
Where are proteins made in a cell?
A
On the ribosomes
18
Q
Note three structures found in plant cells that are not found in animal cells
A
Cell wall Chloroplasts Permanent vacuole
19
Q
What is the function of cell sap?
A
To support the cell - giving strength to non-woody plants.
Contains the materials needed for the plant’s health, e.g., sugars, amino acids, wastes, mineral salts.
20
Q
Where is DNA found in bacteria?
A
Floating plasmids
21
Q
Arrange in order of size (largest to smallest) bacterium, liver cell, nucleus, ribosome
A
Liver cell Nucleus Bacterium Ribosome
22
Q
What is a micrometre?
A
1x10-6(m)
23
Q
What is an ecosystem
A
All the organisms living in a habitat and all the non-living parts of that habitat
So - snails and rocks!
polar bears and ice!
24
Q
Define biological competition
A
Living species trying to get enough resources to survive
25
What is interdependence?
Different species relying on each other for food, shelter, pollnation, seed dispersal...
If one species is removed, it can affect the whole community.
26
Define abiotic
non-living
"a"- as a prefix means "without" in Greek
27
Define biotic
"Living"
bios in Greek means life.
28
Define four abiotic factors that affect living communities
light intensity
temperature
moisture levels
soil pH and mineral content
wind intensity and direction
C02 levels for plants
O2 levels for animals
29
Define three biotic factors that can affect a habitat
Changes in food availability
Change in number of predators
Introduction of pathogens/diseases
One species outcompeting another
30
How does a biologist define a population
A group of organisms of one species living in a habitat
31
What are "adaptations"?
Features that organism have that enable them to survive in their normal conditions
32
33
What are extremophiles?
Organisms that live in extreme conditions
- temperature
- pressure
- salt concentrations
Eg. bacteria living on glaciers or near deep sea vents
34
What is a transect line used for?
A line placed across a field on which a quadrat is placed to count species etc
35
What is a stable community to a biologist?
All species and environment factors are in balance so relevant population numbers are stable
36
Describe a chromosome
The nucleus of a cell contains chromosomes made of DNA
Each chromosome carries hundreds of genes.
In body cells, chromosomes are found in pairs with one chromosome coming from each parent.
Humans have 23 pairs,
Dogs have 30 pairs.
37
Describe genes
Genes contain the code to make different proteins and so control the development of different characteristics.
38
Describe the cell cycle
DNA is copied and new chromosomes are made
Cell undergoes mitosis
Each cell grows and makes new sub-cellular structures
DNA is copied...
39
Describe mitosis
A cell grows and increases the number of sub-cellular structures (ribosomes, mitochondria)
The DNA replicates to form two copies of each chromosome
During mitosis:
one set of chromosomes is pulled to each end of the cell
the nucleus divides
the cytoplasm and cell memberanes split to form identical cells
40
Why is mitosis important?
It makes new cells for the organism
- growth
- repair
- asexual reproduction
41
What are stem cells?
Undifferentiated cells
- they have not yet become 'specialised'
They are found in embryos, umbilical cords (embryonic stem cells),
and some organs and tissues (adult stem cells)
42
What are stem cells used for?
- treating conditions where cells are damaged (paralysis, diabetes)
- replace damaged cells
43
What is therapeutic cloning?
Use of patient's own stem cells for replacing damaged cells/tissues
- no risk of rejection
44
What are meristems and why may they be useful?
Special areas in plants that house their stem cells
- easy for cloning the plant
- help clone nearly extinct species
GM crops bred to resist disease
-
45
# Define (cellular) diffusion
Why does it happen?
The net movement of particules across cell membranes from an area of high concentration to an area of low concentration
Because particles move randomly an spread out
E.g., O2 and CO2
Urea from cells into blood
DIgested food molecules into blood
46
What factors affect (cellular) diffusion?
Concentration gradient
Temperature
(think particle theory - more energy, more movement)
Surface area of the membrane
\*Unicellular organisms have large surface area to volume ratio allowing molecules to easily diffuse
\*Multicellular organisms have low surface area to volume ratio, so they have developed specialised cells to help with diffusion: e.g, small intestines, lungs - large surface area, moist.
47
What maintains the concentration gradient in animals?
Rich blood supply
48
What speeds up gaseous exchange in plants
(i.e., keeps the concentration gradient diffusion working?)
Ventilation
49
Define osmosis
The diffusion of water from a dilute solutoin to a concentrated solution through a semipermeable membrane
50
Explain (cellular) active transportation
When substances are moved against a concentration gradient
- this requires energy
E.g., mineral ions brought in from the soil into root hair cells
and sugar molecules from the lower concentration in the gut into the blood stream
\*\*active transport stops in the absence of oxygen or in the presence of metabolic poisons such as cynanide, arsenic, belladonna, and strychnine
51
What happens when cells differentiate?
- may change shape
- have different sub-cellular structures to assist in its specific functions
52
Name some specialist cells
ANIMAL
Nerve cells
Muscle cells
Red blood cells
PLANT
Root hair cells
53
Draw and name the main parts of a motor neuron
54
Draw an name the main parts of a sperm cell
55
Draw and label the main parts of a muscle cell
56
Describe xylem cells
Arranged end to end, end walls break down to form hollow tubes
Cell walls are strengthened by lignin
57
Describe phloem cells
End walls allow sugars through but support the tubes
Arranged end to end into tubes
58
Compare xylem and phloem cells graphically
59
Draw and label a root hair cell
60
What are enzymes?
| (four points)
Biological **catalysts** that speed up reactions in living organisms.
They are large proteins and have an **active site** inside a space
Enzymes do **specific** reactions
And work best at **optimum** temperatures and pH levels
61
What is tissue?
Group of cells with a similar structure and function
62
What is an organ?
Group of diiferent tissues working together to perform a specific job
E.g. stomach contains muscle tissue, glandular tissues (secrete juices), and epithelial (covering) tissue
63
What is an organ system?
Several organs working together to perform a broader function
E.g., Digestive system contains - mouth, oesophagus, stomach, smaller intestine, larger intestine, rectum and anus - and accessories, liver, gall bladder and pancreas.
64
Define an organism
A collection of organ systems that make up an living entity
65
What is denaturing?
When high temperatures or extreme acidic/alkline levels disrupt enzymes such that they denature (fall apart)
66
What is the "lock and key" theory of enzymes?
A model that explains how enzymes seem to work
- the chemical that reacts is the substrate (the key)
- it fits into the enzymes active site (the lock)
Emil Fischer (1894!!)
67
Name four digestive enzymes and their functions
**Protease** - breaks down proteins/amino acide: produced in stomach, pancreas and small intestine
**Lipase** - breaks down fats/oils into fatty acids and glcyerol: produced in pancreas and small intestine
**Carbohydrase** - breaks down carbohydrates
**Amylase** - breaks down starches into sugar (maltose): produced in salivary glands and pancrease
68
What is bile and where is it made?
Bile is an alkaline liquid to neutralise stomach acids,
Bile also emulsifies fats to increase their surface area
Both of which enables enzymes to work quicker on them
It is made in the liver and stored in the gall bladder
69
What is the function of the epidermis on a leaf?
Epidermis - 'top layer of skin' - covers the outer surfaces of the plant for protection
70
What happens in the pallisade mesophyll in a leaf?
It's the main site for photosynthesis
71
What is the function of spongy mesophyll in a leaf?
It has air spaces to all gases to diffuse through the leaf
72
What do xylem vessels do in a leaf?
They transport minerals and water from the roots and also help support the plant.
"Reach for the xy..."
xy rhymes with sky
73
What do phloem vessels do in a plant?
They transport dissolved sugars through the plant (from leaves downward)
This is called translocation
phloe = flow down
74
What is meristem tissue in a plant?
Meristem tissue is found at the tips of the roots and shoots where new cells are produced for root growth
75
Is a leaf a plant organ?
Yes
76
What process describes how water enters plant root cells?
Osmosis
77
Through which cells does water evaporate and diffuse out of a plant
Stomata (small pores)
78
What term is used to describe the loss of water from leaves?
transpiration
79
What factors affect transpiration?
* Temperature (higher = more transpiration)
* Wind (faster air flow = higher rate of evaporation)
* Light (more light, stomata open more)
* Humidity (increase = less transpiration as concentration gradient for diffusion of water into the air is lower)
*
80
What is the function of guard cells in a plant?
They open and close stomata
81
why are stomata closed at night?
They close because carbon dioxide is not needed for photosynthesis, so closing the stigmata reduces water loss.
82
Explain how guard cells work
1. When water is plentiful the guard cells take up water and become turgid (swollen).
2. This causes the stigmata to open.
3. So gases for photosynthesis are free to move in and out of the stigmata along with water from transpiration.
4. BUT when water is scarce losing water makes this tomato change shape and close.
5. This stops the plants from losing water through transpiration.
83
What is translocation?
The movement of food (dissolved sugars) through the phloem tissue in a plant.
84
What is a pathogen?
Microorganisms that cause infectious (communicable) diseases
85
How are pathogens spread?
Direct contact
Water
Air
Vectors (other organisms that carry the pathogen which don't get the disease themselves)
86
How can the spread of infectious diseases be hindered?
1. Hygiene
2. Increasing immunity through diet/gut flora (post GCSE answer!)
3. Destroying vectors
4. Isolating infected persons
5. Vaccines (potentially - side effects/increased viral resistance)
87
Name some viral diseases
Measles
Human immunodeficiency HIV -\> can cause AIDS
Human papilloma virus HPV
Polio
Shingles
Chicken Pox
Common cold
Influenza
Rabies
Hepatitis
Warts
PLANTS
Tobacco mosaic virus (TMV)
88
How do bacterial pathogens affect healthy cells?
They can damage cells directly
or they produce toxins that damage tissues
89
Explain how salmonella is introduced and affects the body
1) It is a bacterial infection
2) It is ingested from food (chickens, eggs) that is not cooked properly or prepared unhygienically
3) The bacteria secrete toxins that can cause fever, diarrhoea
\* potential defence: vaccinating chickens.
90
How is gonorrhea spread and what are its symptoms?
Bacteria transmitted sexually
Thick yellow/green discharge from the vaine/penis with pain urinating
Treated with penicillin but evidence of resistance
Avoidance/protection: abstinence/condoms
91
What are protists?
What widespread disease (which calls more people than any other on the planet) is due to protists?
Single celled eukaryotic organisms
Malaria
The protist uses a specific mosquito which passes it into human blood upon sucking blood.
Malaria causes fever and can be fatal.
Prevention is with nets around the bed, although it seems that people of African genes have a greater immunity than Europeans say.
92
What kind of disease is Rose Black Spot?
It's fungal.
Fungal spores are carried on the wind to affect plants.
The infected leaves develop black spots, turn yellow and drop off early.
A decrease in foliage causes the plant to not grow as fast as photosythesis is reduced.
Treated with fungicides and burning affected material.
93
What are pathogens?
Microorganisms that enter the body and cause disease
94
What are communicable diseases?
Diseases that can easily spread
95
What are bacteria?
Very small cells- reproduce rapidly
96
Are viruses cells?
No- they’re 1/100th the size of a bacterium
97
What do viruses do?
Live inside cells, use cells machinery to replicate then burst releasing virus
98
What do viruses do to make you feel ill?
Cell damage
99
What are Protists?
Single celled eukaryotes
100
What are parasites transferred by?
A vector
101
What is hyphae?
A thread like structure of fungi
102
What do hyphae do?
Grow and penetrate human skin and the surface of plants causing disease
103
What are the three ways pathogens can be spread?
Water, Air and Direct Contact
104
Name 3 viral diseases
Measles, HIV and tobacco mosaic virus
105
What are the symptoms of measles?
Red skin rash and signs of a fever
106
How is measles spread?
Droplets- sneezes or cough
107
How is HIV spread?
Sexual contact or bodily fluids (blood)
108
What are the symptoms of HIV?
Flu like symptoms
109
What time of cells does HIV attack?
Immune cells
110
What does TMV affect?
Plants
111
TMV symptoms on a plant?
Mosaic pattern of leaves and discoloured
112
Why can’t TMV infected plant carry out photosynthesis?
Because of the discolouration
113
Name a fungal disease?
Rose black spot
114
What does rose black spot do to plants?
Cause black spots on rose plants and leaves drop off
115
How does rose black spot spread?
Through water or wind
116
Name a diseased cause by a protist?
Malaria
117
What vector carries malaria?
Mosquito
118
How can people be protected from malaria?
Insecticides and mosquito nets
119
Name 2 bacterial diseases
Salmonella and Gonorrhea
120
What is salmonella?
Type of bacteria that causes food poisoning
121
What are the symptoms of salmonella?
Fever ,stomach cramps, vomiting and diarrhoea
122
How can you get salmonella?
Eating food that has been contaminated with salmonella bacteria
123
How is salmonella prevented?
Poultry are given vaccinations against salmonella
124
What is Gonorrhoea?
Sexually transmitted disease
125
Symptoms of Gonorrhoea?
Pain when urinating, thick yellow discharge
126
How is Gonorrhoea prevented?
Antibiotics and barrier methods when having sex (comdoms)
127
4 ways spread of disease can be reduced
Being hygienic, destroying vectors, isolating infected individuals , vaccination
128
The largest organ that helps acts as a barrier is?
Skin
129
What in your nose trap particles that could contain pathogens?
Hair and mucus
130
What does the stomach produce to kill pathogens?
Hydrochloric acid
131
What kicks in if pathogens make it into your body?
Immune system
132
What is the most important part of your immune system?
White blood cells
133
Name 3 ways white blood cells attack invading microbes?
Consuming them(phagocytosis), Producing antibodies, producing antitoxins
134
What are in vaccinations?
Small amounts of dead or inactive pathogens
135
What does the MMR vaccine contain?
Measles, mumps and rubella
136
Pros of a vaccine
Control lots of diseases that were common, prevents epidemics
137
Cons of a vaccine
Don’t always work, can have a bad reaction
138
What drug relieves pain?
Pain killers (aspirin, paracetamol)
139
What kills bacteria?
Antibiotics
140
2 ways bacteria could be resistant to antibiotics
Bacteria mutate or if you have an infection
141
What are the resistant bacteria called?
Resistant strain
142
What can the resistant strain do to the body?
Cause a serious infection that can’t be treated by antibiotics
143
How can doctors slow down the rate of resistant strains?
Not to over prescribe antibiotics
144
Name the drug that comes from willow
Aspirin
145
Name the drug that comes from foxgloves
Digitalis
146
Who discovered penicillin
Alexander Fleming
147
Three stages of drug testing
Human cells and tissues, 2 live animals, human volunteers in a clinical trial
148
What produces antibodies?
B-lymphocytes
149
What are monoclonal antibodies produced from?
Lots of clones of white blood cells
150
What do tumor cells do?
Divide lots so they can be grown easily
151
B-lymphocytes and tumor cells bind to make what?
Hybridoma cell
152
What do hybridoma produce?
Monoclonal antibodies
153
What are monoclonal antibodies useful?
They target a specific cell
154
Name something monoclonal antibodies are used in?
Pregnancy tests , treat diseases (cancer), research (measure hormone levels)
155
Side effects of monoclonal antibodies?
Fever, vomiting and low blood pressure
156
3 diseases plants get?
Bacterial, viral and fungal
157
Signs a plant has a disease
Stunted growth, spots on leaves, patches of decay, abnormal growth, malformed stems, discolouration
158
How can you identify a plants disease?
Gardening manual or internet, taking to a laboratory, testing kits
159
What are plants physical defences
Waxy Cuticle, cell walls (contain cellulose), dead cells around stems
160
What are plants chemical defences?
Antibacterial chemicals (mint plant and witch hazel), produce poisons (deadly nightshade and foxglove)
161
What are plants mechanical defences?
Thorns and hairs, leaves that droop or curl, plants mimic other organisms (ice plant family- look like stones)
162
which side of the heart does de-oxygenated blood enter?
the right side
163
what if the heart mainly made of?
muscle tissue
164
how does the heart keep the blood flowing in the right direction?
valves to stop back flow
165
through which artery does oxygenated blood leave?
aorta
166
how do muscles in the heart keep your resting heart rate controlled?
producing electrical impulses which spread through the heart causing them to contract
167
what are two features of an artery?
1. walls are strong and elastic so it can cope with high pressure 2. thick walls compared to the lumen
168
what are two features of a capillary?
1.permiable walls so substances can diffuse in and out 2. supply cells with food and oxygen and take away waste like CO2
169
what are three features of a vein?
1. thin walls because blood at lower pressure 2. large lumento help blood flow 3. valves to keep blood flowing in right direction
170
what is the main function of red blood cells?
to carry oxygen around the body
171
what is the main function of white blood cells?
to defend against infection
172
what is the main funtion of platelets?
to help blood clot
173
what is conorary heart disease?
the conorary arterie gets blocked by layers of fatty material building up so less oxygen is supplied to the heart
174
what are stents used for?
tubes inserted inside arteries to keep them open and allow blood to flow
175
what are statins used for?
drugs that reduce amount of 'bad' cholesterol in your bloodstream
176
what procedures can be done if there is a heart faliure?
transplants of the whole heart or valves
177
what can be used when a lot of blood is lost?
artificial blood like a salt solution or a blood transfusion
178
what are non communicable diseases?
diseases that cannot spread between people or animals and people
179
Name three types of non comunicable diseases?
asthma, cancer and coronary heart disease
180
what are 3 factors that can effect your health?
diet, stress and life style choices (including alcohol, drugs, promiscous sex, poverty)
181
what are 4 risk factors that directly cause a disease?
1. smoking 2.obesity 3.alcohol 4.exposure to certain radiation
182
what causes cancer?
uncontrolled cell growth and division which forms a tumour
183
what are two types of cancer?
1.benign- stays in one place and isnt cancerous 2. malignant-tumour grows and spreads to neighbouring tissues, cancerous
184
