Cell structure Flashcards
What do both forms of cells consist of?
Cell membrane
Cytoplasm
Ribosomes
What plant spesific organells are there?
Cell wall
vacuole
Chlorolplasts
What are bacteria cells?
Prokaryotes
What are the organelles of bacteria cells?
Cell membrane ribosomes cell wall circular strand of dna (plasmids) Cytoplasm
Why do we estimate the size of cells?
to small to directly measure size
What are the different specilised cells?
sperm nerve muscle root hair cell xylem phloem
How is sperm specilisied?
head of the sperm contains the genetic material for fertilisation
middle piece is packed with mitochondria to release energy needed to swim and fertilise the egg
tail enables the sperm to swim.
How are nerve cells specilisied?
nerve cell is extended, so that nerves can run to and from different parts of the body to the central nervous system
How are muscle cells specilisied?
contain filaments of protein that slide over each other to cause muscle contraction
mitochondria to provide the energy for muscle contraction
How are root hair cells specilisied?
large surface area to provide contact with soil water. It has thin walls so as not to restrict the movement of water.
How are xylem cells specilisied?
no top and bottom walls between xylem vessels, so there is a continuous column of water running through them
Their walls become thickened and woody. They therefore support the plant.
(made of dead cells)
How are phloem cells specialised?
- Sieve tubes - specialised for transport and have no nuclei. Each sieve tube has a perforated end so its cytoplasm connects one cell to the next.
- Companion cells - transport of substances in the phloem requires energy. One or more companion cells attached to each sieve tube provide this energy.
(made of living cells)
What are genes?
Short sections of DNA which code for building proteins - characteristcs
What is a geneome?
The entire genetic material of an organism
What is a mutation?
A change in the gene, chromosome or DNA sequence
3 reasons we study the human genome?
Search for genes which are linked to disease
Unserstanding the human genome will help treat inherited disorders
We can trace human migration patterns from the past
What is the process of meisosis?
Cell from testies or ovaries (46 chromosomes)
1 - DNA replicates
2 - Cell divides twice
3 - 4 daughter cells form - gentically different - contain a single set of chromosomes
What is the equation for binary fission?
Starting population X2 to the power of number of divisions
How often does bacteria normally replicate?
Every 20 minutes by binary fission
What does binary fission depend on?
availability of nutrients and other suitable conditions, such as temperature.
What are two ways to grow or culture bacteria
nutrient broth solution or colonies on an agar plate
What does Nutrient broth solution do?
It allows a liquid or gel to provide all the nutrients needed for bacteria to grow successfully.
What nutrients are needed for Nutrient broth solution, or culture medium?
carbohydrates for energy, nitrogen for protein synthesis, plus other minerals
How is an agar plate created?
By pouring hot molten agar into sterile petri dishes, which is then allowed to set
What can you use to transfer bacteria?
An inoculating loop
How do you sterilise an inoculating loop?
By heating it to red hot in a Bunsen flame, before and after use.
What does the lid on the petri dish do?
the lid prevents micro-organisms from the air contaminating the culture
How do you inoculate an agar plate
lift the lid of the Petri dish and tilt
At what temperature are Inoculated agar plates incubated at? For how long?
25°C in school laboratories for no more than 24–48 hours.
What is a prokaryotic cell?
A simple cell that does not have a nucleus – the DNA is free in the cytoplasm. (made up of prokaryotic cells)
What is a eukaryotic cell?
A type of cell that has a nucleus. (made up of eukaryotic cells)
What are plasmids?
small rings of DNA
can replicate
Do prokaryotes contain mitochondria?
No
What is the process to prepare an uncontaminated culture?
Pre inoculation:
- Petri dish and agar sterilised before use to kill unwanted bacteria
- Inoculating loop passed through flame to sterilise/kill other bacteria
Inoculation:
- Use loop to spread bacteria on agar
- Open as little as possible to prevent microbes entering from air
Post inoculation:
- Sealed with tape
- Incubate
What is the zone of inhibition?
area in which ecoli has been destroyed/no longer growing
What is the process of mitosis?
1) DNA replicates to form 2 copies of each chromosome
2) Sub celleur structures multiply
3) Cells grow
4) Sub celleur structures pulled to each side of the cell
5) Chromosomes and their copies seperateand then cell dividies
What is the name for cell division?
Cytokinesis
What are the results of mitosis?
- 2 daughter cells
- Genetically identical
What can mitosis be used for in terms of cells?
- Repair
- Development
- Growth
