Multicellular Organisms Flashcards
What do a group of cells form?
A tissue
What do different tissues combine to form?
Organs
What do different organs form?
Body systems
Name two adaptations of sperm?
Has a tail to swim Lots of mitochondria as it is very active
Name two adaptations of red blood cells?
Biconcave shape to increase surface area It has no nucleus so it has more space for haemoglobin, which carries the oxygen
Name two adaptations of neurons?
They are long and thin to allow swift transfer of impulses The axon is covered in insulator
Name an adaptation of root hair cells?
Long roots for large surface area
What are stem cells?
Stem cells are unspecialised animal cells that can divide and develop into any type of body cell, allowing growth and repair
What is the most basic stem cell?
The embryonic stem cell
Where are the stem cells found in plants?
They found in the meristem tissues, which are located at the shoots and roots
How can the nervous system be split up?
Into the CNS and the nerves
What does the CNS compose of?
The brain and spinal cord
What does the cerebrum control?
Conscious thought and memory
What does the Cerebellum control?
Controls balance and co-ordination
What does the Medulla control?
Breathing and heart rate
What are three types of neuron?
Sensory, relay and motor
What does the sensory neuron do?
Carries nerve impulses from the stimuli to the CNS
What does the relay neuron do?
It transmits the impulses from the sensory neuron to the motor neuron
What does the pancreatic, adrenal, testicular and ovarian glands produce?
Pancreatic= Insulin and glucagon Adrenal= Adrenaline Testicular= Testosterone Ovarian= Oestrogen
What is a synapse?
A gap between the nerve ending of one neuron and another cell
What passes through a synapse to allow the impulse to carry on moving?
A neurotransmitter is released by active transport
What system releases hormones?
The endocrine system
What is the function of insulin?
Stimulates the formation of glycogen from glucose molecules
What is the function of glucagon?
Stimulates the breakdown of glycogen to make glucose molecules
Where are gametes formed?
In the gonads
How many set of chromosomes do gametes have and what is this called?
They have 1 set and this is called their haploid number
Where does the sperm flow in ejaculation?
Sperm is produced in the testes, passes along the sperm duct and passes out of the body via the urethra which contained in the penis
Describe the movement of the egg in a female
The egg is released from the ovaries into the oviduct. If not met by a sperm cell, after 3-4 weeks it moves to the uterus where it released as a period
What happens when the sperm and egg meet?
The two nuclei fuses and produce a zygote
Label all parts of the diagram
Anther, Stigma, Filament, Style, Petals, Ovary, Sepod and ovule
What is Pollination?
Pollination is the transfer of pollen grains from an anther to a stigma
How does pollen fertilise the ovules?
Once the pollen grain has landed onto the stigma, it grows a pollen tube towards the ovaries. Once connected it sends its nucleus down the tube to fuse with the ovules
What is created when two gametes fuse?
A zygote
What are the two types of variation?
Discrete and Continous
What is discrete variation?
It is when the characteristic falls into distinct groups
What is continous variation?
It is when a characteristic can have any value within a range
What does the term polygenic suggest?
The characteristics displayed are controlled by more than one gene
When will a dominant allele be expressed as the phenotype?
A dominant allele will always be expressed if one allele is present
When will a recessive allele be expressed as the phenotype?
When there are no dominant alleles present
What does the term homozygous describe?
When two alleles for an organism characteristic are the same
What does the term heterozygous describe?
When the two alleles are different
What is the function of the waxy cuticle?
Waterproof layer to minimise water loss
What is the function of the upper epidermis?
Its colourless to allow light to pass through
What is the function of the palisade cells?
Contains lots of chloroplasts for photosynthesis
What is the function of the spongy mesophyll layer?
Has air spaces to allow gas exchange
What is the function of guard cells?
Change shape due to the movement of water
Describe Xylem vessels
Xylem are one way, hollow cells that are strengthened by lignin. They transport water and salts and hydrate the plant
Describe Phloem tissue
Phloem is a vascular tisse composed of sieve tubes, sieve plates and companion cells. Its function is to carry sugar to areas of photosythesis
What is transpiration?
The loss of water from the leaves through the stoma
When what four things increase, increase rate of transpiration?
Temperature, Humidity, Wind, Light intensity
What are the 4 chambers of the heart called?
Left and right atrium and ventricle
Describe the function and structure of arteries
Arteries can high pressure blood away from the heart. They have thick muscular walls and a narrow central channel
Describe the structure and function of veins
Veins carry low pressure blood to the heart. They have thinner muscular walls and a wide channel. They also have valves to prevent back flow
Describe the function and structure of capillaries
To allow diffusion of materials between the blood and muscle. They form networks around muscles and have one cell thick walls and have a large surface area
What are the branching parts which make up your airways?
Trachea-bronchus-bronchioles-alveoli
What are the 4 adaptations of alveoli for efficient gas exchange?
- Small size and shape provides large surface area
- Surronded by dense capillary network
- Alveolus has a one cell thick wall
- The lining of the alveoli is moist
What organ absorbs most of our food?
The small intestine
What is absorbed into the capillary ina villi?
Glucose and amino acids
What is absorbed into the lacteal in a villi?
Fatty acids and glycerol
Name two adaptations to allow efficient food absorption in the small intestines?
Many villi for large surface area and the villi’s wall is 1 cell thick
