B1 Biology Top 41 Flashcards
What is the independent variable?
This is the variable that you control. It is changed to see how the dependant variable will change.
What is the dependant variable?
The dependant variable is the variable you measure as an outcome of the experiment.
What are three differences between a prokaryote and a eukaryote?
Prokaryote - Smaller, no nucleus, older, simpler, no membrane bound organelles, DNA located in cytoplasm
Eukaryote - Bigger, nucleus, younger, complex, membrane bound organelles, DNA located in nucleus
What are three organelles found in a plant cells not in animal cells?
Cell wall, chloroplasts, vacuole
What is the function of the mitochondria?
For respiration
What is the function of the ribosomes?
For protein
What are three differences between a bacteria and animal cell?
Bacteria - Smaller, no nucleus, older, simpler, no membrane bound organelles, DNA located in cytoplasm
Animal cell - Bigger, nucleus, younger, complex, membrane bound organelles, DNA located in nucleus
What is the formula for calculating magnification when using a microscope?
magnification = size of image/actual size
What are two advantages of an electron microscope?
Better resolution, Better magnification
How many μm are in a mm?
1000
What are two adaptations for a sperm cell?
Tail to swim to the egg, lots of mitochondria for energy
What are two adaptations of a root hair cell?
Big surface are to move water into cell, large vacuole to store water
What is the role of the xylem?
To transport water and nutrients around the plant
What is the role of the phloem?
Transports food around the plant that has been made from photosynthesis
What does the term differentiation mean?
When a stem cell turns into a specialised cell
What is a stem cell?
Undifferentiated cells that have the potential to develop into many different types of cells
What are two ways stem cells can treat disease?
Can replace organs, grow new organs
Why are some people against the idea of using stem cells to treat disease?
That it could be potential life and can’t consent to the operation
Where are stem cell found in plants?
The tips of roots and shoots
How many chromosomes are in a normal human cell?
46 (23 pairs)
How do prokaryotic cell reproduce?
Binary fission
A bacterium divides once every 20mins. How may will there be after 3 hours?
512
A bacterium divides once every 15mins. How may will there be after 1hr and 30mins?
64
What is a gene?
The short end of a chromosome that carries the DNA
What are the two parts of the cell cycle?
Mitosis, growth and DNA replication
What is mitosis used for?
Growth and repair
What can you say about the cells produced by mitosis?
They are identical
How do you describe mitosis in simple terms?
The chromosomes copy, line up at the centre of the cell and then divide. Protein fibres pull them apart then the cell membrane and cytoplasm divide.
What is diffusion?
Movement of particles from areas of high concentration to areas of low concentration (down a concentration gradient)
What are three factors that affect diffusion?
Temperature, surface area, distance, concentration gradient
What are four features of exchange surfaces to make them more effective?
Thin so short diffusion pathway, large surface area, good blood supply, moist for gas to dissolve
What are four adaptations of the villi?
Large surface area, moist for gas to dissolve, good blood supply, thin so short diffusion pathway
What are four adaptations to speed up diffusion?
Stomata allows gases to diffuse to maintain concentration gradient, thin so short diffusion pathway, air spaces and flattened shape increase surface area, moist for gas to dissolve
What is osmosis?
Movement of water particles through a partially permeable membrane from an area of high water concentration to area of low water concentration.
What is the formula for calculating percentage change in mass?
change in mass/original × 100
What happens to a plant cell when it is placed in pure water and why?
Swells and becomes turgid as water moves in by osmosis, from high water concentration to low water concentration.
What happens to a plant cell when it is placed in a concentrated solution and why?
Shrivels and becomes plasmolysis as water moves out by osmosis, from high water concentration to low water concentration.
What is active transport?
Movement of substances from low to high concentration (against a concentration gradient)
What does active transport require?
Energy from respiration
What is an example of active transport in plants?
Absorbing minerals from soil
What is an example of active transport in humans?
Absorbing substances such as glucose in small intestine or kidney
