biology Flashcards
1
Q
What is biomass?
A
Biomass is the living material in plants and animals.
2
Q
What is dry mass? What are the advantages and disadvantages?
A
Method of measuring dry biological material
- Must kill the animal
- Measured in grams
- More accurate results than wet mass as it is more precise
- Can be problematic for certain animals (dogs and cats…etc)
3
Q
What is wet mass? What are the advantages and disadvantages?
A
Method of measuring wet biological material
- Do not kill the animal
- Measured in grams
- Less accurate as the amount of liquid varies in animals throughout the day
4
Q
Give two differences in structure between eukaryotic and prokaryotic cells.
A
Prokaryotic cells are smaller and simpler than eukaryotic cells which are complex and include all animal and plant cells, whereas prokaryotic cells include bacteria.
5
Q
Name the features that plant cells have that animal cells do not have.
A
- Ridgid cell wall
- permanent vacuole
- chloroplast
6
Q
What is the nucleus of a cell?
A
It controls all the activity that goes on in a cell and contains the genetic material.
7
Q
What is the cytoplasm?
A
It is a gel-like substance that fills the cell and is where all reactions take place.
8
Q
What is the cell membrane?
A
Controls what goes in and out of the cell
9
Q
What are the mitochondria?
A
Where most reactions to aerobic respiration take place.
10
Q
What are the ribosomes?
A
It is where proteins are made in the cell.
11
Q
What is a rigid cell wall?
A
Made out of cellulose, it supports and protects the cell
12
Q
What is the permanent vacuole?
A
It contains cell sap
13
Q
What is the chloroplast?
A
Where photosynthesis occurs. It contains a green substance called chlorophyll which absorbs the light needed for photosynthesis.
14
Q
What type of organisms are bacteria?
A
Prokaryotes
15
Q
Which microscope gives a higher solution and why? A light microscope or an electron microscope?
A
An electron microscope because they use electrons.
16
Q
What is cell differentiation?
A
Differentiation is a process in which a cell changes in order to become specialized for its job.
17
Q
Give three ways in which a sperm cell is adapted for swimming to an egg cell.
A
- Long tail and streamline head to help with swimming
- Lots of mitochondria for energy
- Carries enzymes to digest through an egg cell
18
Q
How is a nerve cell specialized in order to send rapid signals?
A
- nerve cells to carry electrical signals
- the cells are long to cover distances
- branched out connections to connect to other nerve cells
19
Q
How is a root hair cell specialized in order to absorb water and minerals?
A
-Big surface area for absorbing water and mineral ions
20
Q
How are phloem and xylem cells specialized in order to transport substances?
A
- They form tubes which transport things such as food and water around plants
- to form them they are joined from end to end
- hollow so things can flow through them
21
Q
What are chromosomes?
A
They are coiled up lengths of DNA molecules.
22
Q
What is the cell cycle?
A
The cell cycle is a cycle that makes new cells for growth, management, and repair.
23
Q
What are the main 2 stages in the cell cycle and explain what happens?
A
Growth and DNA repair:
- A cell that’s not dividing- DNA spreads out into long strings
- Before it divides- cell grows and increases the number of subcellular structures, like mitochondria
- then duplicates its DNA- this forms x-shaped chromosomes
Mitosis:
-Chromosomes line up at the center of the cell and cell fibers pull them apart. Two arms go onto opposite ends
-Membranes form around each set. These become the nuclei of the two new cells-nucleus divided
-cytoplasm and cell membrane divide
2 NEW DAUGHTER CELLS- IDENTICAL TO PARENTS
24
Q
Give two ways that embryonic stem cells could be used to cure diseases.
A
- stem cells transferred from the bone marrow of a healthy person can replace faulty blood cells
- embryonic stem cells can replace faulty cells in sick people- such as insulin-producing cells to someone with diabetes
25
Why might some people be against using human embryos in stem cell research?
- kills potential human life
| - should develop other sources than embryos
26
What is diffusion?
Movement of particles from a high concentration to a low concentration.
27
What are some substances that can diffuse through cell membranes?
- glucose
- amino acids
- water
28
What are some substances that can't diffuse through cell membranes?
- starch
| - protein
29
What types of molecules move through osmosis?
water molecules
30
What is osmosis?
The movement of water molecules across a particularly permeable membrane from a region of high water concentration to a region of low water concentration.
31
What are the 2 main differences between active transport and diffusion?
- Diffusion's molecules move from a high concentration to a lower concentration, however, for active transport, it is the opposite
- Diffusion does not require energy, however, active transport does
32
What are some similarities between active transport and diffusion?
- they are both about the movement of ions
| - both travel across the cell membrane
33
Give 2 ways in which the villi in the small intestine are adapted for absorbing digested food.
- they have a single layer of surface cells
| - good blood supply to assist easy absorption
34
Give 2 ways in which the alveoli are adapted in order to maximize diffusion.
- enormous surface area
- moist lining for dissolving gasses
- thin walls
- good blood supply
35
Give 2 adaptations of exchange surfaces that increase the efficiency of diffusion.
- having a large surface area for greater exchange – achieved by having a folded surface
- having a thin exchange surface for a short diffusion distance
36
Explain how leaves are adapted in order to maximize the amount of carbon dioxide that goes into their cells.
-Large surface area To absorb more light
Thin Short distance - for carbon dioxide to diffuse into leaf cells
Chlorophyll - Absorbs sunlight to transfer energy into chemicals
Network of veins - To support the leaf and transport water and carbohydrates
Stomata - Allow carbon dioxide to diffuse into the leaf
37
What is a tissue?
A tissue is a group of similar cells that work together to carry out a particular function.
38
Explain what is meant by the term 'organ system'
An organ system is a group of organs that work together in order to perform a particular function
39
Why can enzymes be described as biological catalysts?
They can be described as this because enzymes reduce the need for high temperatures and we only have enzymes to speed up the useful chemical reactions.
40
Why do enzymes only catalyze in one reaction?
This is because enzymes only have one active site, which is only complementary to one specific substrate.
41
What does it mean when an enzyme has been denatured?
This means that the shape of the enzymes active site has changed and so the substrate won't fit anymore.
42
Describe how you could investigate the effect of a pH on the rate of amylase activity.
I could do this by:
- Dropping iodine solution into every well of a spotting tile
- put a beaker of water on a tripod and heat the water to 35*
- Keep water temp constant
- Add different amounts of water to the starch solution
- mix the components and start a timer
- see how long it takes for the amylase solution to break down all the starch solution
- repeat with different pH solutions
- control variables for a fair test
43
List 3 places where amylase is made in the human body.
- the salivary glands
- the pancreas
- the small intestine
44
What is the role of lipases?
Lipases convert lipids into glycerol and fatty acids
45
Where is bile produced, stored, and released?
Bile is released in the liver, stored in the gallbladder, and released into the small intestines.
46
Name the solution that you would use to test for the presence of liquids in a food sample.
Tyndall Beam Effect (shine a light on the food)
47
Name the tubes that split off the trachea
Bronchiole
48
Explain the role that alveoli play in gas exchange.
The alveoli carry out gas exchange.Oxygen diffuses from the air in the alveoli into the blood.
Carbon dioxide diffuses from the blood into the air in the alveoli.
49
Explain why the circulatory system in humans is often referred to as 'the double circulatory system'.
This is because humans have two circuits joined together- the right ventricle and the left ventricle.
50
What kind of blood does the left ventricle pump?
oxygenated blood
51
What kind of blood does the right ventricle pump?
deoxygenated blood
52
Why does the heart have valves?
In order to make sure blood flows in the right direction- prevent it from flowing backwards.
53
Name the 4 chambers of the heart.
The right atrium, right ventricle, left artium, and the left ventricle.
54
How is the resting heart rate controlled in a healthy heart?
It is controlled by a group of cells in the right atrium that act as a pacemaker.
55
How are arteries adapted to carry blood away from the heart?
The heart pumps blood out at a high pressure so:
- the artery walls are strong and elastic
- thick lumen
- layers of muscles to make them strong
- elastic fibers allow them to spring back
56
Why do red blood cells not have a nucleus?
They don't have a nucleus so that they can have more space to store more oxygen
57
Give 2 advantages and 2 disadvantages of statins.
ADV:
- reduces the amount of 'bad' cholesterol so they reduce the risk of heart attacks
- Increase beneficial cholesterol (HDL cholesterol)
DIS:
- A long-term drug that must be taken regularly, a risk of someone forgetting to take them
- negative side effects such as kidney failure, liver damage, and memory loss
58
What is meant by non-communicable disease?
Cannot spread between people or animals. They generally last for a long time and get worse as time goes by. Asthma, coronary heart disease, and cancer are examples.
59
What is the difference between biological and mechanical replacement heart valves?
Biological valves are from humans or other mammals. Mechanical valves are man-made.
60
Give an example of where different types of a disease might interact in the body.
- Some types of cancers: can be triggered by an infection by certain viruses.
- Mental health: depression can be caused by someone with physical health problems
61
What is meant by risk factor of a disease?
Risk factors are things that are likely linked to increase in the likelihood that person will get a disease.
62
What type of tumor is cancerous?
Malignant because they invade healthy tissues and spread to other parts of the body through the bloodstream.
63
List the tissues that make up a leaf.
Epidermal
Mesophyll
Xylem
Pholem
64
Explain how the structure of the upper epidermal tissue in a leaf is related to its function.
It's transparent so that light can pass through to the palisade layer.
65
What is the function of phloem?
Delivers water and other nutrients to the entire leaf and takes away the glucose produced by photosynthesis.
66
What is transpiration?
It is the loss of water from a plant.
67
List the 4 main things that affect transpiration.
- Light intensity: brighter, greater transpiration
- Temp: warmer, faster transpiration
- Air flow: better air flow, greater transpiration
- Humidity: drier, faster transpiration
68
Name the type of cell that helps open and close the stomata.
Guard cells
69
What type of tumor is not cancerous?
Benign: stays in one place and grows until no room
70
How can bacteria make us feel ill?
Bacteria can make you feel ill by producing toxins that damage your cells and tissues
71
How does tobacco mosaic virus affect a plant's growth?
It causes a mosaic pattern which then colors the leaves so that they can not carry out photosynthesis and it effects the growth.
72
What are the symptoms of gonorrhea (which is a sexually transmitted disease)?
- Pain when urinating
| - Yellow or green discharge from the vagina or penis
73
What are pathogens?
They are microorganisms that enter the body and cause diseases.
74
In what ways are pathogens spread?
- Water: by drinking dirty water eg.cholera
- Air: can be carried in air droplets produced when you cough or sneeze eg.influenza
- Direct contact: touching skin eg. athletes foot by using the same towels
75
What are the 3 viral diseases?
- HIV: spread by sexual contact
- Tobacco mosaic virus: effects plants
- Measles: spread by droplets
76
How are mosquitos involved in spreading malaria?
They pick up the infection from other people and when they bite others the disease is then transmeted
77
How can destroying vectors help to prevent the spread of disease?
It gets rid of what spreads the disease and therefore the disease then stops spreading.
78
What does the stomach produce that can kill pathogens?
hydrochloric acid
79
Give 3 ways that the white blood cells can defend against pathogens.
- ingest pathogens and destroy them
- produce antibodies to destroy particular pathogens
- produce antitoxins that counteract the toxins released by pathogens.
80
Give 1 pro and 1 con of vaccination.
PRO
-help control lots of communicable diseases that were once common such as, polio
CON
-don't always work
81
Which plant does the painkiller aspirin originate from?
willow
82
What type of pathogen can antibiotics be used to kill?
Bacteria
83
What two things are drug tested on in preclinical testing?
- animals
| - human volunteers
84
What is a placebo?
A substance that does not do anything but people do not know that.
85
Where in a plant does photosynthesis take place?
Takes place in chloroplasts in green plant cells
86
What is an endothermic reaction?
energy is transferred from the environment
87
Why do plants store glucose as starch?
stores it like this so that it can be used when photosynthesis is not happening and is stored as starch because it is insoluble
88
What is meant by a 'limiting factor' of photosynthesis?
what limits the amount of photosynthesis that can take place these can be:
- light
- CO2 concentration
- temperature
89
What effect would a low carbon dioxide concentration have on the rate of photosynthesis?
Photosynthesis would go slower.
90
What is respiration?
the process of transferring energy from the breakdown in glucose-goes on in every single cell continuously.
91
What is an exothermic reaction?
An exothermic reaction is a chemical reaction that releases energy by light or heat
92
Name the products of aerobic respiration.
carbon dioxide and water
93
Name 2 products in the food and drink industry that fermentation is needed for.
bread
| alcoholic drinks
94
What is the word equation for anaerobic respiration in yeast cells?
glucose------ethonal+carbon dioxide
95
In what organ is lactic acid converted back into glucose?
Liver (check w teacher)
96
Give 3 things that increase to supply the muscles with more oxygenated blood during exercise.
-respiration
-breathing volume
-breathing rate
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97
Explain how negative feedback helps to maintain a stable internal environment
When the level of something is too high or low your body uses negative feedback in order to bring it back to back to normal
98
What makes up the central nervous system and what does it do?
Central nervous system: brain and spinal cords
Sensory neutrons: carry receptors
Motor neutrons: carry electrical receptors from the CNS to effectors
Effectors: muscular and glands which responds to nervous impulses
99
What is a synapse?
The connection between 2 neurons is called a synapse.
100
Explain how negative feedback helps to maintain a stable internal environment
When the level of something is too high or low your body uses negative feedback in order to bring it back to back to normal
101
What makes up the central nervous system and what does it do?
Central nervous system: brain and spinal cords
Sensory neutrons: carry receptors
Motor neutrons: carry electrical receptors from the CNS to effectors
Effectors: muscular and glands which responds to nervous impulses
102
What is a synapse?
The connection between 2 neurons is called a synapse.
103
What is the purpose of a reflex action?
Help prevent injury.
104
Give 2 differences between a nervous and hormonal response.
Hormonal: act in a more general way
act for a longer time
Nervous: Act for a very short time
act for a very precise area
105
Describe the action of the fuse in a circuit.
- stops the flow of electrons if the current of it goes over 5A
- Does this by melting and breaking the current
106
What is heterozygous
One dominant and one recessive
107
What is homozygous
Two recessive or two dominant
108
What is asexual reproduction
one parent
No fusion of gametes
No mixing of chromosomes
Offspring are clones
