B1: Cell Biology Flashcards
What is a Cell?
The fundamental building blocks of life
What is an eukaryotic cell?
A complex cell such as an animal or plant cell
What is a prokaryotic cell?
A smaller and simpler cell compared to eukaryotes, such as Bacteria Cells
What is the Nucleus’ function?
To store genetic material and control activities in cells
What is the cytoplasm?
It’s a gel-like substance where most chemical reactions take place contains enzymes
What is a Cell Membrane?
It controls what goes in and out of the cell, holds cell together
What are the functions of a ribosome?
To create proteins
What is the function of the mitochondria?
Where aerobic respiration takes place, transfers energy to the cell
What is the function of the cell wall?
Made from cellulose to support the cell and strengthen it
What is the role of the permanent vacuole?
Contains cell sap (solution of sugar and salts)
What is the role of the chloroplast?
The place where photosynthesis takes place makes food for the plant cell. It contains chlorophyll which absorbs light
What is a plasmid, where is it found?
A small ring of DNA found in Bacteria cells
How is DNA stored in Bacteria Cells?
A single circular strand of DNA which floats freely in the cytoplasm
What is the equation for magnification?
magnification = image size ÷ real size
What is used to highlight cells when used on a microscope
iodine solution
What is put on top of the stained cells in onion experiment?
Cover Slip
What microscope is stronger?
Electron, light is weaker
What is meant by resolution
The ability to distinguish between two points
What is cell differentiation
when the cell becomes specialised for its job
What is difference between animals and plants with cell differentiation
In animal cells it only happens during early stages however plants dont lose this ability ever
What are undifferentiated cells called
stem cells
How are sperm cells specialised
A long flagellum and streamlined head helps it swim to the egg. loads of mitochondria to provide it with enough energy
How are nerve cells specialised
Have axons which are really long to get throughout the body, myelin sheath makes the electrical currents travel faster
How are muscle cells specialised
Contract quickly and contains loads of mitochondria
How are root hair cells specialised
They have no chloroplast beacause they are underground so cant absorb light, have a large surface area to absorb more water + mineral ions
How are phloems and xylems specialised
Allows substance to be transported
How many pairs of chromosomes does a human have (normally)
23 pairs, 23 from your mother, 23 from your father
what does most of cell cycle consist of?
growth and DNA replication (mitosis is the rest)
What happens before mitosis
mitochodria and ribosomes increase (amount) DNA duplicates and form X-shaped chromosomes.
What happens during Mitosis
Chromosomes line up in the centre and two arms of each chromosome go to opposite ends of the cell.
Membranes form on each side, these become nuclei (the nucleus has split)
Lastly the cytoplasm and cell membranes divide
What are the cells called after mitosis
2 identical daughter cells
What is Binary fission
How prokaryotic cells replicate
What is used to grow bacteria
Petri Dishes which have agar jelly inside
At what temp. should a culture be kept at, at school? why?
25C, harmful pathogens are likely to grow above that temp
What is the circle around the antibiotics called in a petri dish
the inhibition zone, the place where bacteria can’t grow
How do you sterilize an incubating loop
You place it over a bunsen burner until it turns yellow
How should the petri dish be placed
upside down to avoid the condensation to drop down, taped too
Where can stem cells be found
In bone marrow (adults), embryos
What is a risk of growing stem cells
Could become contaminated by a virus
Why are some people against stem cell research
Because they believe you are making the human life suffer, Only God can take life
Where are stem cells found in plants
In meristems, it can be differentiated at any time in its life
What can meristems be used for
To create identical copies of plants
What is diffusion?
The movement of partivels from an area of higher concentration to an area of lower concentration
What are factors of cell membranes
The concentration gradient (directly proportional), surface area (directly proportional)
What is osmosis
movement of water molecules from a higher concentration to a lower concentration through a partially permeable membrane
