1 Cell 2 Flashcards
Name 6 specialised cells? Which are in humans and which are in animals?
Muscle cell, Sperm cell and Nerve cell in animals
Root hair cell, phloem and Xylem in plants
What is a stem cell?
An undifferentiated cell which has the capacity to become any type of cell.
Name the places you can find stem cells in a human
Bone marrow and embryonic cells
What is Therapeutic cloning?
using adult cells to produce a cloned embryo of an adult to provide perfectly matched embryonic stem cells
What’s the function of sperm cell and how is it specialised for this function?
- reproduction (get the make DNA to the female DNA)
- long tail and a streamlined tail to swim to the egg
- many mitochondria to provide energy
- enzymes to digest through the egg membrane
What’s the function of a nerve cell and how is it specialised for this function?
- rapid signalling (carry electrical signals from different parts of the body)
- the cells are long to cover more distance
- branches connections at the ends to connect to other nerve cells
- form a network
What’s the function of a muscle cell and how is it specialised for this function?
- contractions
- they’re long (so have space to contract)
- contain lots of mitochondria to generate energy for contraction
What’s the function of a root hair cell and how is it specialised for this function?
- specialised for absorbing water and minerals
- has long ‘hair’ that stick out into the soil which gives the plant a big surface area
- for absorbing water and minerals ions
What’s the functions of Phloem and Xylem and how are they specialised for their functions?
- phloem and Xylem cells form phloem and Xylem tubes, which transport substances (food and water) around the plants
- Xylem are hollow
- phloem have a few sub-cellular structures
- so stuff can flow through them they both form tubes.
What’s differentiation?
- the process by which a cell changes to become specialised for its job
- when they change they develop different sub cellular structures and turn into different types of cells, and carry out specific functions
When does most differentiation occur in an organisms?
- most animals cells differentiate at an early cell
- (when they differentiate in mature animals it’s for repairing and replacing cells like skin or blood cells)
- plants mostly retain the ability to differentiate through there life times
How do prokaryotic cells (bacteria) replicate?
- binary fission, where one cell splits in half into 2
- the plasmids replicate and move to opposite ends of the cell, the cytoplasm divides and a new wall is formed
- 2 daughter cells are produced
- (in the right conditions sone bacteria can replicate in 20 minutes)
What are 2 conditions which are optimal for binary fission?
A warm environment and lots of nutrients
What’s a culture medium?
It’s where bacteria are grown in contains: minerals, proteins, vitamins, etc.
-it can be a nutrient solution or Colonies on an ager gel plate
In school labs what temperature are cultures if microorganisms kept at?
- not above 25 C
- because more harmful pathogens are more likely to grow above this temperature
How must you prepare an uncontaminated culture?
- petri dishes & culture mediums: must be sterilised by heating at a high temperature to kill unwanted microorganisms on them
- inoculating loops: used to transfer microorganisms to the culture must be sterilised by passing them through a flame
- the lid of the Petri dish should be tightly taped on (after transferring the bacteria) to stop microorganisms for the air getting in
- the Petri dish should be stored upside down to stop condensation falling onto the agar surface
- incubated at 25 C
What do chromosomes do?
Where are they found?
- found in the nucleus, your genetic material is in form of chromosomes
- there’s 2 copies of every chromosome (One has been inherited from the mother, the other from the father)
- Humans have 23 pairs of chromosomes (there found in pairs), so 46 in total
- each chromosome has different genes so control the development of different characteristics
What’s the name of the complete set of chromosomes for a species?
karyotype
Why would mitosis happen?
- Growth, to make the organism bigger
- Repair of damaged tissues or replacement of worn-out cells
- Asexual reproduction
What’s the cell cycle?
- the time between the formation of a cell and when it undergoes cell division
- the division is mitosis because the new cells formed must contain all of the genetic information of the previous cells
What are 2 stages of the cell cycle?
- Growth and DNA replication
2. mitosis
Explain the full cell cycle
- the cell grows then increases the number of sub-cellular structures (ribosomes, mitochondria)
- The DNA replicate and forms 2 copies of each chromosome. And forms X-shaped chromosomes
- in mitosis the chromosomes line up in the centre of the cell and cell fibres pull them apart. 2 arms of each chromosome go to opposite sides
- membranes form around each set of chromosomes, the nuclei
- then the cytoplasm and cell membrane divide
What’s produced in mitosis?
- 2 new daughter cells
- they contain the sane genetic information there DNA is also identical to the parent cell
