Cell Biology

What does magnification mean

how many times bigger the image is than the object

What does resolution mean

the ability to distinguish between 2 points

What’s the equation to calculate magnification

size of image divided by size of real object

what cell parts are in both plant and animal cells

• nucleus

• cytoplasm

• cell membrane

• mitochondria

• ribosomes

what cell parts are in just plant cells

• cell wall

• vacuole

• chloroplasts

what’s the function of the nucleus

contains genetic material

what’s the function of cytoplasm

where chemical reactions happen

what’s the function of the cell membrane

controls what goes in and out of the cell

what’s the function of mitochondria

where respiration occurs

what’s the function of ribosomes

where proteins are made

what’s the function of the cell wall

made of cellulose, supports cell shape

what’s the function of the vacuole

contains sap

what’s the function of chloroplasts

where photosynthesis occurs (contain chlorophyll)

what is a specialized cell

a cell that’s adapted to a specific function e.g. sperm cells

what is differentiation and how is it different between animals and plants

• the process where a cell changes to become specialized

• in animals only stem cells can become specialized

what are the features of bacterial (prokaryotic) cells

• no nucleus - instead have a free single strand of DNA

• may also contain small loops of DNA called plasmids

• no mitochondria or chloroplast

• cell wall

how is genetic information stored in the nucleus of a cell

• DNA - in a molecule

• Genes - sections of DNA that code for a particular characteristic

• Chromosomes - DNA is in long chains with many genes. Humans have 23 pairs

what is the process that happens during the cell cycle

1. before a cell can divide it needs to grow and increase the number of cell structures e.g. ribosomes and mitochondria

2. the DNA replicates to form two copies of each chromosome

3. in mitosis - the chromosome copies are moved into two new cells

4. one set of chromosomes is pulled to each end of the cell and the nucleus divides

5. the cytoplasm and cell membranes divide to form two identical cells

where are stem cells in plants

meristmes

where are stem cells found in animals

human embryos and bone marrow

what are special about stem cells

they can differentiate into specialised cells

what’s a use of stem cells in plants

• cloning plants

• can save rare species and also create many copies of a crop with desired characteristics

how can stem cells be used in medical treatments

• replace faulty cells in sick people

• nerve cells for paralysis by spinal injuries

• therapeutic cloning - can be used to create tissue with the same genetic information so reduce rejection

what are the potential risks/issues with using stem cells in medical treatments

ethical issues - using embryos in research (each one is a potential life)

what is diffusion

the movement of particles from an area of higher concentration to an area of lower concentration

what are the factors that affect the rate of diffusion

• higher temperature increases rate (speed) of diffusion as the particles move faster

• higher concentration gradient leads to an increased rate of diffusion

what happens to the “surface area to volume ratio” of objects as they get bigger

the smaller the object the bigger the surface area to volume ratio

how does the surface area to volume ratio affect single-celled and multicellular organisms

• single celled organism can get gases directly across the cell membrane

• larger organisms need lungs to increase their surface area and get enough oxygen

how are the small intestines and lungs adapted for maximum diffusion rate

they have a good blood supply to maintain a concentration difference

describe the process of osmosis

the movement of water molecules from a higher water concentration to a lower water concentration across a partially permeable membrane