paper 1 Flashcards
Describe what is meant by the term eukaryotic
A eukaryote is an organism whose cells contain a nucleus within a membrane.
What 3 organelles are present in plant cells but not in animal cells?
cell wall, chloroplasts, vacuole
What do bacterial cells have instead of a nucleus?
The DNA is found in the nuceloid, a region with no membrane, or as a plasmid, a small circle of extra genetic information, floating right in the cytoplasm, the fluid that fills the cell.
What is the equation to calculate magnification?
magnification = image size / actual size
What is the equation to calculate image size?
magnification = image size / actual size
Why do you stain cells before looking at them under the microscope?
To enhance visualization of the cell or certain cellular components
Define the term specialised cell
cells that have developed certain characteristics to perform a particular function
What are the 6 types of specialised cells you need to know?
Sperm cells, nerve cells, muscle cells, root hair cells, phloem and xylem cells
How many chromosomes are there in a human cell?
46
What are the 3 main stages of the cell cycle?
Growth, DNA replication, mitosis
Describe the individual steps in mitosis
1) The chromosomes line up at the center of the cell
2) The 2 arms are pulled apart to opposite sides of the cell
3) The nucleus divides
4) Each set of chromosomes becomes the new nucleus of the cell
5) The cytoplasm and cell membrane divide
6) A new cell is created
What is a stem cell?
Cells that have not yet differentiated into different types of cells
Why are there ethical issues surrounding stem cells?
Some people think embryos shouldn’t be researched because they could be human life.
What are meristem cells used for in plants?
A meristem is the tissue in most plants containing undifferentiated cells (meristematic cells), found in zones of the plant where growth can take place.
Define the term diffusion
Diffusion is the spreading out of cells from an area of high concentration to lower concentration
Define the term osmosis
Osmosis it the movement of water molecules across a partially permeable membrane from a high concentration to lower concentration
Define the term active transport
Substances being absorbed from a lower concentration to a higher concentration - against the concentration gradient.
Give 2 examples of where active transport occurs
Root hair cells and in blood
How can you observe the effect of sugar solutions on plant tissues
Using a microscope
How are the alveoli adapted for gas exchange
Very thin, loads of them, large surface area
Define the term tissue
A tissue is a group of similar cells that work together to carry out a function
What is an catalyst
A catalyst is a substance which increases the speed of a reaction, without being used up or changed
Describe the lock and key model
Every enzyme has an active site with a unique shape. The substrate involved with the enzyme has to fit that specific shape.
What enzyme breaks down proteins
Protease
How would you test for a protein
Biuret test
What would a positive result be for the iodine test
The colour of the solution would change from a browny-orange to a black or blue.
How would you test for a lipid
The Sudan III test or ethanol
What would a positive result be for the benedict’s test
The solution would turn from a blue colour to green, yellow or brick red.
Describe the path of a red blood cell in the left side of the heart
The blood would enter the left atrium via the pulmonary vein, be pumped out of the left ventricle through the aorta back to the body
Describe the structure of an artery
Strong, elastic, muscly, travel away from the heart, carry high pressure blood
Describe the structure of a vein
Thinner walls, have valves, travel towards the heart, low pressure blood
Explain the functions of the 4 components of blood
Red blood cells carry oxygen, white blood cells fight infection, platelets help blood clot, plasma carries all the blood
What is a coronary artery
An artery that supplies the heart muscle with blood
How can you reduce the risk of coronary heart disease
Eat healthy, exercise
Give 3 examples of both communicable and non-communicable diseases
1) chicken pox, flu, cold
2) cancer, parkinsons, diabetes
What is a non-cancerous tumor called
Benign
Why are malignant tumors life threatening
They get into healthy tissues and form secondary tumours
Describe the function of a xylem cell
transport water from roots to leaves
What is translocation
Movement from one place to another
Describe how viruses reproduce
The virus injects its nucleic acid into the cell. The nucleic acid takes over the normal operation of the host cell and produces multiple copies of the virus’s protein coat and nucleic acid.
What are 2 types of bacterial diseases and how are they passed on
Salmonella through raw food, gonorrhea though unprotected sex
What is malaria spread by
Malaria is spread by mosquitos which carry the Plasmodium protist.
How does our immune system attack pathogens?
Phagocytes and lymphocytes kill the pathogens
How do vaccinations protect from future infection
the wbc’s already have antibodies against the illness
What are 3 drugs that come from plants and what plants do they come from
Aspirin from willow bark, digitalis from foxgloves, opium from poppys
How do new drugs become available
They are tested loads
What is the equation for photosynthesis
carbon dioxide + water (light) —> glucose + oxygen
How do plants use glucose
- to make cell walls
- turned into starch and stored
- for respiration
What is metabolism
the chemical processes that occur within a living organism in order to maintain life.
What are the equations for anaerobic respiration in humans and plants
For humans - glucose -> lactic acid
for plants - glucose → ethanol + carbon dioxide
glucose symbol
c6h12o6
What do mitochondria do?
Release energy
Aerobic respiration
What do ribosomes do?
Make protein
