Cells and Cell Processes Flashcards
DNA structure (Double Helix)
Sides = twisting strands of sugar phosphate backbone Rungs = base pairs
DNA function
To create information used by cell for protein synthesis (process where cells make what they need)
4 bases
Adenine, Thymine, Guanine, Cytosine
Complimentary pairs
A + T
G + C
Proteins are made from what?
Amino acids
Scientists that led to discovery of structure of DNA?
Watson and Crick
When enzyme and substrate join, chemical reactions take place where?
Active site
When substrate binds to enzyme’s active site?
Enzyme-substrate complex
At low temperatures enzyme activity is slow. Why?
Kinetic energy.
Particles move more slowly so less collisions
What happens when enzyme gets too hot?
It denatures.
This is when bonds inside the enzyme begin to break so the active site changes
What temperature does enzyme work fastest?
Optimum temperature
3 main types of digestive enzymes and what they break down:
- Lipases = break down lipids (fats) into fatty acids and glycerol
- Carbohydrases = break down carbohydrates (e.g. starch) into simple sugars
- Proteases = break down proteins into amino acids
Cell division that leads to growth and repair (create genetically identical copies)
Mitosis
Cell division that leads to the formation of sex cells (gametes)
Meiosis
What happens when a cell reproduces by mitosis?
Splits to create 2 identical cells
What happens when a cell reproduces by meiosis?
Splits in half to form new cells with half the number of chromosomes to produce gametes for sexual reproduction
When two gametes join in fertilisation, the number of sets of chromosomes is restored
Definition of a stem cell
Undifferentiated cell with the ability to divide into a differentiated cell
Where are stem cells found?
- bone marrow
- umbilical cords
- unborn embryos
- meristem in plants
E.g. of differentiated cell
Nerve cell
Function of leaf cell and how it’s structure allows them to carry this out
To absorb light energy for photosynthesis.
Cell is adapted to be filled with chloroplasts. Cells are tightly packed together to create layer that efficiently absorbs sunlight
Structure of animal cell
Nucleus
Cytoplasm
Cell membrane
Structure of plant cell
Nucleus Cytoplasm Cell membrane Cell wall Chloroplasts Vacuole
Structure of bacterial cell
Cytoplasm
Cell membrane
Cell wall
Structure of yeast cell
Cytoplasm Cell membrane Nucleus Cell wall Vacuole
Structure of algal cell
Nucleus Cytoplasm Cell membrane Cell wall Chloroplasts Vacuole
Structure of virus cell
Protein coat Nucleic acid (just a few genes)
How do yeast cells reproduce?
Divide by Budding
How do viruses reproduce?
Inside a host cell
Microbe largest in size?
Yeast
How do bacteria reproduce?
Dividing in 2
2 ways in which microbes are useful for humans
- Yeast can be used to make bread
- Bacteria can form from spores in high or low temperatures
One way microbes are dangerous to humans
Viruses reproduce within a living cell so they can kill cells
Name given to a group of genetically identical organisms
Clones
How enzymes work and give an example (QWC)
- Work by lock and key method
-Enzyme joins to substrate and turns substrate into new substrate
-Temperature too hot = enzyme denatures and won’t work
-Temperature too cold = reaction too slow, no collisions, no reactions because no kinetic energy
-Examples:
·Protease + proteins = amino acids
·Lipase + fat = fatty acids + glycerol
·Amylase + starch = glucose
