B1 Cell Biology

Question 1

what is a cell

Answer 1

The smallest unit of living matter

Question 2

what organelles are found in plants only

Answer 2

chloroplasts, vacuole, cell wall

Question 3

define the nucleus

Answer 3

contain genetic information which control the activities of the cell

Question 4

define the cytoplasm

Answer 4

most chemical reactions take place here(controlled by enzymes)

Question 5

define the cell membrane

Answer 5

controls the movement of substances into an out of a cell

Question 6

define the mitochondria

Answer 6

most energy is released by respiration here

Question 7

define ribosomes

Answer 7

where protein synthesis takes place

Question 8

define the cell wall

Answer 8

strengthens the cell

Question 9

define chloroplasts

Answer 9

contains chlorophyll which absorbs light energy for photosynthesis

Question 10

define the permanent vacuole

Answer 10

filled with cell sap

Question 11

name 3 advantages of light micropscopes

Answer 11

cheep to buy
colour images can be obtained
can view living specimens

Question 12

name 3 disadvantages of light microscopes

Answer 12

limited magnification
depth of field is restricted
limited resoloution

Question 13

name 3 advantages of electron microscopes

Answer 13

high resolution
greater depth of field
high magnification

Question 14

name 3 disadvantages of electron microscopes

Answer 14

expensive to buy
living specimens cannot be obtained
images are black and white

Question 15

what is the equation for magnification

Answer 15

magnifictaion = image size
actual size

Question 16

define diffusion

Answer 16

the movement of substances from and area of high concentration to an area of low concentration down the divsion gradient, it is a passive process

Question 17

what is a partially permeable membrane

Answer 17

where there is space fro a small volume of particles to enter or leave

Question 18

define active transport

Answer 18

the movement of particles from an area of low concentration to and area of high concentration, against the division gradient using energy

Question 19

define osmosis

Answer 19

the diffusion of water from a dilute to a concentrated soloution across a partially permeable membrane passive process

Question 20

what is the risk assessment for the osmosis RPA 1

Answer 20

care should be taken
cutting potato cylinders
using electrical balance in the presence of water

Question 21

what is the apparatus required for the osmosis RPA 1 (name at least 5 )

Answer 21

potato
ruler
10cm3 measuring cylinder
labels boiling tubes
a test tube rack
knife
salt soloution
distilled water

Question 22

what is the method for the osmosis RPA2

Answer 22

1. cut 3 potato cylinders and make sure the are all the same length
2. measure and record the mass of each potato cylinder
3. measure 10cm3 of the 0,5 salt solution and put into the first boiling tube label the boiling tube 0.5m salt
4. do the same fro all salt solution
5. add one potato cylinder to each boiling tube
6. leave the potato cylinders in the boiling tubes overnight in the test tube rack
   7.remove the potato cylinders from the boiling tubes and carefully blot them dry
7. re-measure the length and mass of each cylinder and record the meaurements on the table
8. record the results on a graph

Question 23

define DNA

Answer 23

the chemical from which chromosomes are made

Question 24

genes

Answer 24

a small packet of information controlling a characteristic

Question 25

chormesome

Answer 25

thread like structures holding genes

Question 26

define mitosis

Answer 26

the division of cells to create 2 identical daughter cells

Question 27

what are stem cells

Answer 27

undifferentiated cells meaning they have no specific function

Question 28

what are embryonic stem cells

Answer 28

cells that can differentiate into any other type of cell

Question 29

what are adult stem cells

Answer 29

found in the bone marrow of adults. they only have limited number of cells they and differentiate into

Question 30

What are sperm cells specialised to do

Answer 30

Sperm cells are specialised for reproduction

Question 31

What is the function of a sperm cell

Answer 31

To get the male DNA to the female DNA

Question 32

What are two adaptations of a sperm cell

Answer 32

There are a lot of mitochondria in the cell to provide the energy it needs It also carries enzymes in its head to digest through the egg cell membrane

Question 33

What are nerve cells specialised for

Answer 33

Nerve cells are specialised for rapid signalling

Question 34

What is the function of a nerve cell

Answer 34

To carry electrical signals from one part of the body to another

Question 35

How are nerve cells adapted for their function

Answer 35

The cells along the cover more distance and have branched connections at their ends to connect other nerve cells and form a network throughout the body

Question 36

How are muscle cells specialized for their function

Answer 36

Muscle cells are specialised for contraction

Question 37

What is the function of a muscle cell

Answer 37

To contract quickly

Question 38

How are muscle cells adapted to their function

Answer 38

The cells are long so that they have space to contract and they contain lots of mitochondria to generate the energy needed for contraction

Question 39

How are root hair cells specialised for their function

Answer 39

Root hair cells are specialised for absorbing water and minerals

Question 40

What is the function of a root hair cell

Answer 40

Root hair cells are cells on the surface of plant roots which grow into long hairs that stick out into the soil

Question 41

How are root hair cells adapted to their function

Answer 41

They have a large surface area for absorbing water and mineral ions from the soil

Question 42

How are phloem and xylem cells specialized for their function

Answer 42

Phloem and xylem cells are specialised for transporting substances

Question 43

What is the function of phloem and xylem cells

Answer 43

Phloem and xylem cells form phloem and xylem tubes, which transport substances such as food and water around plants to form the tubes. The cells are long and joined end-to-end

Question 44

How are phloem and xylem cells adapted to their function

Answer 44

Xylem cells are hollow in the centre and phloem cells have very few subsellular structures so that stuff can flow through them

Question 45

What are the three stages to cell growth and DNA replication

Answer 45

Step 1: in his cell that's not dividing, the DNA is all spread out in Long strings Step 2: before it divides, the cell has to grow and increase the amount of sub cellular structures such as mitochondria and Step 3: the cell then duplicates its DNA– so there's one copy for each new cell. The DNA is copied and forms x shaped chromosomes. Each 'arm' of the chromosome is an exact duplicate of the other

Question 46

What are the three stages of mitosis

Answer 46

Step 1: the chromosomes line up at the center of the cell and cell fibers pull them apart. The two arms of each chromosome go to opposite ends of the cell Step two: membranes form around each of the sets of chromosomes. These become the nuclei of the two new cells. The nucleus has divided Step 3: lastly the cytoplasm and the cell membrane divide full stop the cell has now produced two new daughter cells. The daughter cells contain exactly the same DNA. They are identical. Their DNA is also identical to the parent cell

Question 47

What are the two main stages of the cell cycle

Answer 47

DNA replication and mitosis

Question 48

What is the stage of the cell cycle when the cell divides called

Answer 48

Mitosis

Question 49

What do multicellular organisms use mitosis for

Answer 49

To grow or replace cells that have been damaged

Question 50

How do prokaryotic cells reproduce

Answer 50

Binary fission

Question 51

What are the four stages to binary fission

Answer 51

Step 1: the circular DNA and plasmids replicate Step two colon The cell gets bigger and the circular DNA strands move to opposite ends of the cell Step 3: the cytoplasm begins to divide and new cell walls begin to form Step 4: the cytoplasm divides and two daughter cells are produced each daughter cell has one copy of the circular DNA but can have a variable number of copies of the plasminants

Question 52

What is differentiation

Answer 52

Differentiation is the process by which a cell changes to become specialized for its job

Question 53

How can stem cells be used

Answer 53

Medicine uses adult stem cells cure disease. Embryonic stem cells can also be used to replace full p cells in sick people

Question 54

What are some risks of using stem cells

Answer 54

Stem cells grown in a lab may become contaminated with a virus which could be passed on to a patient and make them even more unwell

Question 55

What are some reasons why people are red against stem cell research

Answer 55

(1) some people are against stem cell research because they feel that human embryos shouldn't be used for experiments since each one is a potential human life (2) campaigners for the rights of embryos feel that scientists should concentrate more on finding and developing other sources of stem cells so people could be helped without having to use embryos (3) in some countries stem cell research is banned, but it's allowed in the UK as long as it follows strict guidelines

Question 56

What part of a plant can stem cells be found in

Answer 56

Meristems

Question 57

what is the process of theraputic cloning

Answer 57

therapeutic cloning involves removing the nucleus (containing the DNA) from a patient's cell (like a skin cell) and transferring it into a donor egg cell that has had its own nucleus removed. This egg cell, now with the patient's DNA, is stimulated to divide and develop into an embryo. After a few days, stem cells can be extracted from this embryo. These stem cells are genetically identical to the patient because they carry the same DNA. The extracted stem cells can be cultured to differentiate into various cell types, potentially replacing damaged or diseased tissues or organs in the patient. For example, they could be used to repair spinal cord injuries, replace damaged pancreatic cells in type 1 diabetes, or create new heart tissue.

Question 58

what is the method for preparing a slide for the microscopy practical

Answer 58

1) first prepare the slide by adding a drop of water to the middle of a clean slide 2) cut up an onion ( or whatever you are viewing) and separate it out into layers. use tweezers to peel of some of the epidermal tissue from the bottom of one of the layers 3) using the tweezers place the epidermal tissue into the water on the slide 4) add a drop of iodine solution. this stains the onion allowing you to see it more clearly 5) place a cover slip upright on the slide and then carefully tilt and lower it so it covers the specimen. try to avoid any air bubbles as they will obstruct the view of the specimen.

Question 59

what is the method for the microscopy practical

Answer 59

1) clip the slide you've prepared onto the stage 2) select the lowest powered objective lens 3) use the course adjustment knob to move the stage just below the objective lens 4) look down the eyepiece. use the coarse adjustment knob to move the stage downwards until the image is roughly in focus 5) adjust the focus with the fine adjustment knob until you get a clear image of whats on the slide 6) if you need to see the slide with a greater magnification swap to a higher powered objective lens and refocus.