Multicellular organism Flashcards
(127 cards)
1
Q
What is the first step of mitosis
A
In the original parent cell, the chromosomes replicate and double Forming 2 identical chromatids joined in the centre by a centromere
1
Q
What is the second step of mitosis
A
The nuclear membrane breaks down and the chromosomes shorten and thicken, becoming visible under a microscope
2
Q
What is the third step of mitosis
A
The chromatids line up along the equator of the cell
3
Q
What is the fourth step of mitosis
A
Spindle fibres attach to the chromatids
4
Q
What is the fifth step of mitosis
A
Spindle fibres shorten pulling the chromatids apart to opposite poles of the cell
5
Q
What is the sixth step of mitosis
A
The cytoplasm divides and a nuclear membrane forms
6
Q
What is the last step of mitosis
A
2 diploid cells produced, containing the same genetic information as the original parent cell
7
Q
What is a chromatid
A
An exact replica of a chromosome joined together with the chromosome it’s replicating
8
Q
What is the equator of the cell
A
The region in the middle of the cell where the chromatid pairs line up before they are separated to the poles
9
Q
What are spindle fibres
A
The spindle fibres are strand of protein that the cell uses to separate the chromatid pairs from the equator to the poles
10
Q
What is a diploid cell
A
They have two matching sets of chromosomes high are replicated during mitosis
11
Q
What does mitosis do
A
Provides new cells for growth and repair of damaged cells and maintains the diploid chromosome complement
12
Q
What are stem cells
A
Unspecialised cells in animals that can divide in order to self-renew
13
Q
What do stem cells have the potential to do
A
become different types of cells
14
Q
how are stem cells obtained
A
from embryo at a very early stage
15
Q
When can tissue stem cells be found in the body
A
Throughout life
16
Q
What does the specialisation of cells lead to
A
The formation of a variety of cells, tissues and organs
17
Q
What are multicellular organism made up of
A
Tissues and organs
18
Q
Do organisms only perform on function
A
No
19
Q
What are cells in organs specialised for
A
Their function
20
Q
What are groups of organisms that work together called
A
Systems
21
Q
What is the hierarchy
A
Cells-tissues-organs-systems
22
Q
What can a response to a stimulus be
A
A rapid action or a slower response from a gland
23
Q
What does the nervous system consist of
A
The central nervous system and other nerves
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What does the central nervous system consist of
The brain and spinal chord
25
What is the cerebrum
The large folded area of the brain and is responsible for conscious thoughts, reasoning, memory and emotions
26
What is cerebellum
Found at the rear of the brain below the cerebrum an controls balance and coordination movement
27
What is the medulla
Found at the top of the spinal chord and contains groups of neurons that transit electrical impulses to the hearts and lungs to control the heart rate and breathing rate
28
What do electrical impulses do
Carry messages along neurons
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What do chemicals Dow it’s these messages
Transfer the, between neurons at synapses
30
What are the three types of neurons
Sensory, inter and motor
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What do receptors
Detect sensory input/stimuli
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What do sensory neurons do
Pass the information to the CNS
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What do inter neurons do
Operate within the CNS, which
processes information from the senses that require a response
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What do motor neurons do
Enable a response to occur at an effector (muscle or gland)
35
What is the function of the reflex arc
To control reflex reactions in humans
36
What is the purpose of reflexes
To protect the body from harm
37
What can a response to a stimulus be
A rapid action from a muscle or as lower response from a gland
38
What can endocrine glands release
Hormones into the bloodstream
39
What are hormones
Chemical messengers
40
What does a target tissue have
Cells with complementary receptor proteins for specific hormones, so only that tissue will be affected by these hormones
41
What are the roles of insulin and glucagon in the blood glucose regulation
They are released by the pancreas in order to control blood glucose concentration
42
What is glycogen
A storage carbohydrate found in the liver and muscle of animals
43
What are the only cells that are haploid
Gametes
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What are almost all cells in terms of amount of chromosomes
Diploid
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What are the two types of gametes
Egg cells and sperm cells(pollen grains in plants
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What organ produces the egg cell
Ovaries
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What organ produces the sperm cell
Animals: testes
Plants: anthers
48
Where is the female gamete organ found
Ovule
49
What is fertilisation
The fusion of the nuclei of the two haploid gametes to produce a diploid zygote, which divides to form an embryo
50
What contributes to variation in a species
The combining of two parent genes
51
What is discrete variation
variation that tends to have phenotypes that do unto separate categories
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What is continuous variation
variation that shows a wide range of values with each value falling anywhere within the range
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What is a gene
A location on a chromosome where a section of DNA contains the codes for a particular protein
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What is an allele
different forms of genes
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What is a phenotype
the organisms physical appearance
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What is a genotype
a statement of the alleles it has for a characteristic
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What is a dominant allele
A dominant allele always shows in the phenotype, even if the individual only has one copy of the allele
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What is a recessive allele
A recessive allele only shows if the individual has two copies of the recessive allele
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What does homozygous mean
Individuals who are homozygous for a certain ry two copies of the same allele
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What does heterozygous mean
Individuals who are heterozygous for a certain gene carry two different alleles
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What is the letter P used to indicate
The original parents in the cross
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What is F1 used to indicate
The first generation of offspring of the parental types
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What is F2 used to indicate
The second filial generation which is comprised of offspring(s) resulting from a cross of the members of F1 generation
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What is the recessive allele represented by in a monohybrid cross
A lowercase letter
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What is the dominant allele represented by in a monohybrid cross
A uppercase letter
66
What are the reason why the predicted ratios of the offspring phenotypes are not always achieved
Fertilisation is a random process, the sample was not big enough
67
What are the plant organs
Roots stems and leaves
68
What is the upper epidermis
The top layer of the leaf which is thin and transparent to allow light to reach the palisade cells in the layer below
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What is the palisade mesophyll
Main site of photosynthesis column shaped, tightly packed and have many chloroplasts
70
What is the spongy mesophyll
loosely arranged in an irregular shape with air spaces inbetween for gas exchange
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What are veins
Composed of xylem vessels and phloem. The xylem brings water to the leaf cells and the phloem transports sugar from photosynthesis
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What is the lower epidermis
A thin layer that aids the regulation of gas exchange containing stomata and guard cells
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What is the stomata
Openings through which the exchange of ga stakes place which are surrounded by two guard cells
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What parts of the plant are involved in water transport
Root hairs, xylem vessels, spongy mesophyll, guard cells and stomata
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Where does water enter through
The plant root hairs
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Where is the water transported through
Dead xylem vessels
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What is the structure of a xylem vessel
Consisted of dead cells with a thick cell wall strengthened by ring of lignin
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Why are xylem vessels lignified
To withstand pressure changes as water moves through the plants
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What is the structure of a phloem tissue
Composed of two main cell types serve tube cells and companion cells
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What is transportation
Teh process of water moving through a plant and its evaporation through teh stomata
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How does water move from the soil to the air
Through osmosis to the root hairs, through osmosis from the root hairs to the xylem in the root, through osmosis from the xylem to the spongy mesophyll in the leaf, from the spongy mesophyll to the moist air space inside the leaf, water the moves through diffusion from the air space in the leaf through the stomata into the air
82
Describe the process of transpiration
Water on the surface of spongy and palisade cells evaporate into air space and diffuses out of the leaf. More water is drawn out of the xylem cells to replace the water that is lost.
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What are the factors that can speed up the rate of transpiration
Light, temperature, wind speed, humidity, leaf surface area
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How does light affect transpiration
In bright light transpiration increases
85
Explain why light affects transpiration in this way
The stomata open wider to let in more CO2 for photosynthesis
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How does temperature affect transpiration
transpiration is faster in higher temperatures
87
Explain why temperature affects transpiration in this way
Evaporation and diffusion are faster at higher temperatures
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How does wind speed affect transpiration
Faster in windy conditions
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Explain why wind speed affects transpiration this way
Water vapour is quickly removed speeding up diffusion
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How does humidity affect transpiration
Slower in his mid conditions
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Explain why humdidity affects transpiration in this way
It slows down if the leaf is already mois
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How does leaf surface area affect transpiration
More leaf Leads to faster transpiration
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Explain why leaf surface area affects transpiration in this way
larger leaf has mores stomata So more water will be evaporating
94
What does blood contain in mammals
Plasma, red blood cells and white blood cells
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What does blood transport
nutrients, oxygen and carbon dioxide
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How are red blood cells specialised
By being biconcave in shape and having no nucleus and containing haemoglobin
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How do red blood cells transport oxygen efficiently
In teh form of oxyhaemoglobin
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How is oxyheamoglobin made
Oxygen + heamoglobin
99
What are white blood cells
Part of the immune system and are involved in destroying pathogens
100
what are pathogens
Disease-causing micro-organisms
101
What are the two main type of white blood cells involved
Phagocytes and lymphocytes
102
What do phagocytes do
Carry out phagocytosis by engulfing pathogens
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What is the process of phagocytosis
A phagocyte detects a pathogen it captures it by flowing its cell membrane around the pathogen which is then trapped and digested by enzymes
104
What do lymphocytes do
Produce antibodies which destroy pathogens
105
Describe the pathway that oxygenated blood takes through the heart
The blood enters the heart through the vena cava and then enters the right atrium after it contracts the blood then flows to the right ventricle. When that contracts the blood leaves through the pulmonary artery and goes to the lungs. The now oxygenated blood returns to the heart through the pulmonary vein which then enters through the left atrium of the heart and then flows to the left ventricle. It then leaves the heart through the aorta to the rest of the body
106
What is the function of the right atria
Collects deoxygenated blood from the vena cava and passes it to the right ventricle
107
What is the function of the left atria
Collects oxygenated blood form the pulmonary vein and passes it to the left ventricle
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Function of the right ventricle
Collects deoxygenated blood from the right atria and pumps it through the pulmonary artery
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Function of the left ventricle
Collects oxygenated blood from the left atria and pumps it through the aorta
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What is the functions of the heart halves
Between atria and ventricles-to prevent back flow from the ventricles to the atria
Exit of the ventricles- prevent back flow from the arteries to the ventricles
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Function of the aorta
accepts oxygenated blood pumped at high pressure by the left ventricle and distributes it to the body
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Function of the vena cava
Collects deoxygenated blood oozing at low pressure through the veins of the body and passes this blood to the right atria
113
Function of the pulmonary vein
Collects oxygenated blood oozing at low pressure from the lungs and passes this blood to the left atria
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Function of the pulmonary artery
Accepts deoxygenated blood pumped at high pressure by the right ventricle and distributes it to the lungs
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Function of the coronary artery
Accepts oxygenated blood pumped at high pressure by the left ventricle and distributes it to the heart muscles itself
116
What is the structure of an artery
They have thick muscular walls, a narrow central channel and carry blood under high pressure away from the heart
117
What is the structure of a vein
Have thinner walls, a wider channel and carry blood under low pressure back towards the heart
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What do veins contain
Valves to stop the back flow of blood
119
What do capillaries form
Networks at organs and tissues
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What features of capillaries allow efficient exchange of materials
One cell thick walls shortening the diffusion time, in very close contact with body tissue also decreasing diffusion distance
121
What are lungs
Gas exchange organs
122
What do lungs consist of
A large number of alveoli providing a large surface area
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How are oxygen and carbondioxide absorbed to or from the many blood vessels
Through the thin alveolar walls
124
Where are nutrients from the food absorbed into
The villi in the small intestine
125
What do teh large number of thin-walled villi proved
A large surface area
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