Biology B1 Flashcards
What kind of cell is a Prokaryote?
Bacteria
What 2 types of cell can a Eukaryote be?
Plant and Animal
Convert 2700000 into standard form?
2.7x10^6
What are the 4 main components of a Sperm Cell?
Flagellum (Tail)
Middle section (Mitochondria)
Head (Nucleus - 23 Chromosomes)
Acrosome (Tip - digestive enzymes)
What are the components of a Nerve Cell?
Axon (Electrical signals travel along)
Myelin sheath (Stops signal leaks)
Dendrites (Branches)
What mediums can we grow Microorganisms in?
Agar gel plate
Nutrient Broth
How do we work out Bacteria Division?
Bacteria at start x2^n
n = number of divisions
e.g. 20 minute division time
4 start bacteria
in 80 minutes there will be 4 divisions (80/20)
so 5*2^4 = 80 bacteria
What is the first stage of the Cell cycle?
Initial growth stage
Extra ribosomes, mitochondria etc.. are produced.
Explain the Mitosis stage in the Cell Cycle
Chromosomes are replicated
The 2 sets of chromosomes are pulled to opposite ends of the cell, the nucleus then divides.
Explain the third stage of the Cell Cycle
Cell division
The cytoplasm and cell membranes divide, resulting in the production of 2 identical daughter cells.
Why is it important that the daughter cells in mitosis have the same chromosomes?
It is necessary for certain processes requiring identical cells to be produced.
E.g. growth and repair, asexual reproduction
Does Mitosis occur in Eukaryotes or Prokaryotes?
Eukaryotes
What is differentiation?
Where a stem cell changes to become specialised for a job.
Through what process do undifferentiated cells divide?
Mitosis
Where are stem cells in plants found?
Meristems
Positives and Negatives of Embryonic stem cells
-
Potential for life
Can harm the patient
+
Embryos used in research would be disposed of anyway
Curing alive people is more important
Why are Embryonic stem cells better than Bone Marrow?
Adult Marrow stem cells are limited and cannot differentiate into as many specialised cells as an Embryonic one.
How can we preserve plants using stem cells?
Cuttings from a plant can continue to grow if given the correct conditions as meristem cells can differentiate at any time
What are disadvantages of Stem cells?
Stem cell transplants can transfer infections
Ethical reasons
Definition of diffusion
Particles moving to reach equilibrium
Spreading out from a high concentration gradient to a low concentration gradient
How are surface area and diffusion linked?
The larger the surface area the faster the Diffusion rate.
How can we link Concentration gradient and Diffusion?
The steeper the concentration gradient, the faster the rate of diffusion.
Explain Osmosis
The movement of water particles from a high concentration gradient to a low one through a partially permeable membrane.
Do you understand the Potato + sugar experiment?
I cba to explain its on page 21 of the book thingy
What is the Dependent variable?
Thing that you measure
Control variable?
Thing that stays the same
Independent variable?
The one that you change
What is Active transport?
Movement of particles from a low to a high concentration gradient
Uses Energy tho
E.g. root hair cells taking in water/minerals
How does active transport happen in humans?
Active transport is used in the gut when there is a low concentration of nutrients in the intestine but a high concentration in the blood.
What does the speed of gas exchange with environment depend on?
Surface area to volume ratio.
How are some cells adapted to have fast substance exchange?
Large surface area
Thin membrane
What are some examples of substance exchange surfaces?
Villi
Roots
Alveoli
How are Alveoli specialised for gas exchange in the lungs?
Large surface area
Moist lining (dissolving gases)
Thin lining
A good blood supply
