B1 Cell biology Flashcards
What are all living things made up of?
cells
What if the difference between a prokaryotic cell and a eukaryotic cell?
the prokaryotic cell has no neucleusProkaryote is simpler
What is the function of the nucleus?
To contain genetic material that controlling the activities the cell
What is the function of the cytoplasm?
The site where most chemical reactions happen
What is the function of the cell membrane?
To hold the cell together and controls what goes in and out
What is the function of the mitochondria?
to help with aerobic respiration
What is the function of the ribosomes?
To make proteins via protein synthasis
What type of cell are bacteria?
prokaryotes
What is the formula for magnification?
image size/real size
Does a bacterial cell have a nucleus?
no
What is a plasmid?
a circular strand of DNA that floats freely in the cytoplasm
Do bacteria have mitochondria or chloroplasts?
no
What are chloroplasts?
where photosynthesis occurs. they make the food for the plant
What is cell differentiation?
a process where cells become specialised
What are sperm cells specialised for?
reproduction- streamlined head and ling tail
What are nerve cells specialised for?
rapid signalling- long and have branched connections
What are muscle cells specialised for?
contraction- long so they have space to contract
What are root hair cells specialised for?
absorbing water and minerals- big surface area
What are phloem and xylem cells specialised for?
transporting substances-long and hollow
What do chromosomes do?
contain genetic information
Why do we have 23 pairs of chromosomes?
Because we have one from the father and one from the mother
What is the function of the cell cycle?
make new cells for growth, development and repair
What is mitosis?
the stage in the cell cycle where the cell divides
How many stages are there in the cell cycle?
2
What happens in the growth and DNA replication stage?
cell grows and duplicates its DNAincreases sub cellular structures like mitochondria and ribosommes
What are the stages of Mitosis?
chromosones line upcell fibres pull them apart membarnes form about each set of chromosonescytoplasm and membrane divide
How do prokaryotic cells divide?
By binary fission
What occurs in binary fission?
plasmids replicatestrands move to opposite polescytoplasm begins to divide2 daughter cells are produced
A bacterial cell has a mean division time of 30 mins. how many times will it divide in 3 hours?
3 x 60= 180180/30=6 times
What temperature do we culture microorganisms at?
25 degrees
what are embryonic stem cells?
cells that can turn into many different types of cells
Where do we find stem cells?
human embryos
Can adult stem cells turn into any type of cell?
no
What is the difference between embryonic and adult stem cells?
Embryonic can turn into any type of cell Adult cant
How could adult stem cells be used in medicine?
bone marrow cells can replace faulty blood cells
How could embryonic stem cells be used in medicine?
to make insulin producing cells for diabetics
Why are some people against stem cell research?
because they feel human embryos are potential human life and shouldn’t be used for experiments
How can stem cells be used in plants?
to produce identical plants for farmers and help grow rare species
Where are stem cells found in plants?
the merristem
What is diffusion?
the movement of particles from an area of high concentration to an area of low concentration
What is Osmosis?
osmosis is the movement of water molecules from a region of high concentration to low concentration across a partially permeable membrane
What is active transport?
where substances are absorbed against the concentration gradient
What will happen in diffusion if there is a bigger concentration gradient?
the diffusion rate will increase
Does diffusion work in solids and liquids?
Solids- noLiquids- yes
What type of molecules can diffuse through cell membranes?
small molocules
Can oxygen diffuse?
yes
Can starch and proteins diffuse?
no`
What type of processes are osmosis and diffusion?
passive
What type of molecules move in osmosis?
water molocules
is energy required for active transport?
yes
Where is active transport used?
in the gut when there is a lower concentration of nutrients in the gut but a higher concentration in the blood
what do cells use diffusion for?
to take in and remove waste products
What is a surface area to volume ratio?
a measure of how easy it is for an organism to exchange substances with its environment
How are exchange surfaces adapted for maximum effectiveness?
thin membranelarge surface arealots of blood vesselswell ventilated
What is the surface area to volume ratio like on single celled organisms?
large
What is the surface area to volume ratio on multi cellular organisms?
small so specialist structures are needed
What is the function of the lungs?
To transfer oxygen to the blood and remove waste carbon dioxide
How are alveoli adapted for efficient gas exchange?
alveoli have….>enormous surface area >Moist lining
How is the small intestine adapted?
good blood supply villi have a large surface area for food to be absorbed more quickly
How are leafs adapted for efficient gas exchange?
stomata open and closelarge surface area
How are fish gills adapted for efficient gas exchange?
gill filaments provide a large surface arealots of blood capilaries speed up diffusionhigh concentration gradient ensures as much as possible is absorbed
