B1 Flashcards
Name five subcellular structures that both plant and animal cells have
A nucleus, cell membrane, mitochondria, cytoplasm and ribosomes
What three things do plant cells have that animal cells don’t?
Rigid cell wall, permanent vacuole, and chloroplasts
Where is the genetic material found in animal cells?
In the nucleus
Where is the genetic material found in bacteria?
A single circular strand that floats freely in the cytoplasm
What type of organisms are bacteria - prokaryotes or eukaryotes?
Prokaryotes
Which gives a higher resolution - a light microscope or an electron microscope?
Electron microscope
What is cell differentiation?
The process by which a cell changes to become specialised for its job.
Give three ways that a sperm cell is adapted for swimming to an egg cell.
It has a long tail and a streamlined head to help it swim to the egg. There are a lot of mitochondria in the cell to provide the energy needed. It also carries enzymes in its head to digest through the egg cell membrane.
Why is the nerve cell in this shape?
The cells are long and have branched connections at their ends to connect to other nerve cells and form a network throughout the body.
What are chromosomes?
They are coiled up lengths of DNA molecules
What is the cell cycle?
The cycle in which body cells in multicellular organisms divide to produce new cells as part of a series of stages.
What is mitosis uses for by multicellular organisms?
To produce two new daughter cells which contain both the same DNA, are identical. Their DNA is also identical to the parent cell.
Give two ways that embryonic stem cells could be used to cure diseases.
Uses to replace faulty cells in sick people - you could make insulin-producing cells for people with diabetes, nerve cells for people paralysed by spinal injuries, and so on. Medicine uses adult stem cells to cure disease.
Why might some people be opposed to the use of human embryos in stem cell research?
Some people argue that the embryos uses in research are usually unwanted ones from fertility clinics which if they weren’t used for research, would probably just be destroyed.
What is diffusion?
Is the gradual movement of particles from an area of higher concentration to an area of lower concentration.
Name three substances that can diffuse through cell membranes, and two that can’t.
Can’s are oxygen, glucose, amino acids and water. Cant’s are starch and proteins.
What type of molecules move by osmosis?
Tiny molecules
Give the two main differences between active transport and diffusion.
. Active transport moves from a lower concentration to a higher concentration while diffusion moves from a higher concentration to a lower concentration.
. Diffusion moves through a partially permeable membrane while active transport moves through a membrane.
Give three adaptations of exchange surfaces that increase the efficiency of diffusion
They must be moist, have a good blood supply, a large surface area and a short diffusion distance.
Give two ways that the villi in the small intestine are adapted for absorbing digested food.
The folded villi greatly increase the surface area of the intestine, and the villi are made of a single layer of thin cells so there is a shorter diffusion path.
Explain how leaves are adapted to maximise the amount of carbon dioxide that gets to their cells
Leaves are broad with a large surface area so that they are exposed to more light and can maximize light absorption. - They are thin and flat so that carbon dioxide has a shorter distance to diffuse and the diffusion therefore occurs at a faster rate.
