Unit 2 Flashcards
Cells group together to form what?
Tissues
Tissues form what?
Organs
How to stem cells reproduce?
Through mitosis
What is the function of an adult stem cell?
To repair and replace damaged cells
Where does growth in plants take place?
Meristems
Where are meristems found in plants?
Tips of growing shoots and roots
Where is an apical meristem found?
Root tips
Where are lateral meristems found?
Surrounds stem of plant
What does the central nervous system consist of?
The brain and spinal cord
What are some of the main functions of the nervous system?
Send information, co ordinate workings of internal organs, respond to stimuli on the outside
What is the role of the sensory receptors?
To send information about what is happening inside and out to the CNS
What is the role of the cerebrum in the brain?
Enables conscious thought and memory
What is the role of the cerebellum in the brain?
Controls coordination and balance
What is the role of the medulla in the brain?
Controls breathing and heart rate
What is a reflex?
An unconscious action such as pulling away from a hot object
What is your reflex arc?
A simple pathway for the reflex action and is made up of three neurons
What are the three neurons that makes up the reflex arc?
Sensory neuron, reflex neuron and motor neuron
What is the role of the sensory neuron?
It carries information from a receptor to a relay neuron
What is the role of a relay neuron?
It connects a sensory neuron to a motor neuron
What is the job of a motor neuron?
Carries information to an effector (a muscle or gland)
What are the gaps between neurons called?
Synapses
Has the exocrine system got a faster or slower response compared to the nervous system?
Slower
What is controlled by the endocrine system?
Hormonal control
In the endocrine system, what releases hormones into the blood stream?
Endocrine glands
What is the name of cells sensitive to hormones?
Target tissues
What molecule is the only source of energy for brain cells?
Glucose
What is the definition of multicellular?
An organism made up of many cells
After eating is the level of glucose high or low?
High
What is excess glucose stored in the form of and where?
Glycogen in the liver
What helps to promote the conversion of glucose to glycogen?
Insulin produced in the pancreas
The hormone glucagon helps to convert what substance?
Glycogen back into glucose
What causes diabetes?
When someone unable to control blood sugar levels dues to problems producing insulin
What does diploid mean?
A cell that has a double set of chromosomes
What does haploid mean?
A cell that has a single set of chromosomes
What are gametes and where are the produced?
Sex cells, produced in structures called gonads
Where is sperm produced?
In the testes
What is produced in the ovaries?
Eggs or ova
What is fertilisation?
When a male and female gamete fuse to form a zygote
Where does fertilisation in animals take place?
In the oviduct
In plants, what is the female gamete called and where is it produced?
Ovules, produced in the ovary
In plants, what is the male gamete and where is it produced?
Pollen grains, formed in the anther
To reach the ovule, what does the pollen grain have to grow?
A pollen tube
Where does fertilisation happen in plants?
Inside the ovule
What is pollination?
The transfer of pollen in plants
What is variation?
Differences within the same species
What is discrete variation?
When feature can be divided into two or more groups (eg - eye colour)
What is continuous variation?
When a feature has a wide range of values (eg - height)
What is the definition of polygenic?
When something is controlled by more than one gene (continuous variation is polygenic)
What is the definition of monogenic?
When something is controlled by only one gene (discrete variation)
What is phenotype?
The physical appearance of an organism
What is a way of recoding patterns in inheritance?
A family tree
What is albinism?
A condition that results in a lack of skin pigmentation
What is genetic counselling?
When people get advice from family trees
What is inheritance?
How characteristics are passed on from one generation to another
What are characteristics controlled by?
Genes
Genes can exist in different forms called what?
Alleles
What does dominant mean?
When one gene masks the other
What is homozygous?
Two same forms of a gene (BB)
What is heterozygous?
When it is two different forms of a gene (Bb)
What is meant by genotype?
Genetic characteristics of an organism
What is the transpiration stream?
The movement of water from the roots to the leaves
What is transpiration?
The loss of water by evaporation
Where does transpiration take place?
Through openings in the leaves called stomata
What controls the opening and closing of stomata?
Guard cells
Where are stomata found?
On the surface layers of the leaf or upper and lower epidermis
What is the upper epidermis covered in?
A waxy layer called the cuticle
What does the cuticle layer on a leaf help to do?
Cut down on water loss
What does the palisade layer consist of?
Tall cylindrically-shaped cells packed with chloroplasts
What is the spongy mesophyll layer of a leaf?
Layers of green cells which take in CO2 and gives out oxygen during photosynthesis
Water enters the leaf by what process and where?
Osmosis through root hair cells
What is the role of the xylem in a plant?
Helps to transport water up the plant
What does the xylem contain to support the plant?
Lignin
What is role of the phloem in a plant?
Transports sugar and other nutrients to all parts of the plant
Is energy needed to drive transpiration?
No only sunlight
Why can’t organisms carry out diffusion?
As it gets bigger, surface area to volume ration gets smaller
What is the circulatory system?
Blood transports nutrients and oxygen to body and removes CO2
What makes up the circulatory system?
Heart and vessels
How many chambers are in the heart?
Four
What are the two upper chamber of the heart called?
Atria
What are the two lower chamber of the heart called?
Ventricles
Which chambers of the heart receives blood?
Atria
Which chambers of the heart discharge blood?
Ventricles
What to valves do?
Ensure there is no back flow of blood
Blood flows into the heart through what?
Veins
Blood flows out of the heart through what?
Arteries
What are capillaries?
Very thin, connects arteries and veins, large surface area for diffusion
What is blood made up of?
Red blood cells, white blood cells, plasma and platelets
What feature helps the red blood cell do its job?
Bi-concave in shape, no nucleus. Extra space to carry oxygen
What is haemoglobin?
A carrier molecule that’s combines oxygen in the lungs
What does the white blood cells do?
Helps to fight infections
What does plasma in the blood do?
Dissolves CO2
What do platelets in the blood do?
Helps to clot blood
What takes place in the lungs?
The exchange of oxygen and CO2
What lines the trachea and why?
Cilia, moves germs and dirt up and out of the lungs
What helps to keep the trachea open?
Incomplete rings of cartilage
What is mucus and what is its role?
A sticky substance that traps dust and germs
What is at the end of the bronchioles?
Alveoli
What takes place in the alveoli?
Where gas exchange takes place, thin walled and huge surface area
Blood flows through the lungs through what?
Capillaries
How is air moved in and out of the lungs?
The diaphragm contracting
Why is food broken down in the mouth?
To expose a larger surface area for enzymes to act on
What is the oesophagus?
A tube to the stomach
What movement helps to push food down the oesophagus?
Waves of peristalsis
What is in saliva to help break down starch into maltose?
Amylase
What does the liver do?
Removes toxins and produces bile
Which body part absorbs nutrients in food?
Small intestines
What is the role of the large intestine?
Removes water from fecal matter
What is the lining of the small intestine covered in?
Villi
Why is the villi in the lining of the small intestine?
Increases surface area for absorption
What is in the centre of each villus and what does it do?
A lacteal, absorbs end products which are fatty acids and glycerol
What is the name of the fluid that connects the lacteal with the secondary transport system?
Lymph
What does nicotine do the human body?
Causes arteries to narrow. Increases blood pressure
Name two lung diseases caused by smoking
Bronchitis and emphysema
What disease will result if a person is iron deficient?
Anaemia
Why are fat rich diets bad for the human body?
It can create deposits in blood vessels which can restrict blood flow
What organs can long term use of alcohol damage?
Liver, stomach and kidneys
