B1- cell biology

Question 1

What are eukaryotics cells?

Answer 1

Eukaryotic cells are complex and include both plant and animal cells

Question 2

Example of a prokaryotic cell?

Answer 2

e.g bacteria.

Question 3

Eukaryotes are what?

Answer 3

They are organisms that are made up of eukaryote cells

Question 4

A prokaryote is what?

Answer 4

Is a prokaryotic cell (a single celled organism)

Question 5

What is the animal cell made up of?

Answer 5

A nucleus-hold DNA and controls the activities of the cell
Cytoplasm-the gel like substance where most chemical reactions take place
Cell membrane-allows what goes in and out
Mitochondria-where aerobic respiration takes place
Ribosomes-protein is made

Question 6

What does the plant cell have that the animal cell doesn’t?

Answer 6

Cell wall-supports the cell and strengthens it
Vacuole-contains cell sap a weak solution of sugar and salt
Chloroplast -photosynthesis takes place (makes food for the plant)

Question 7

Bacteria cells are what type of organism?

Answer 7

Prokaryotes

Question 8

Structure of bacteria cell

Answer 8

-cell wall
-cell membrane
-cytoplasm
-bacteria cells don’t have a true nucleus instead have singular circular strands of DNA that float freely in the cytoplasm
-one or more ring of DNA called plasmids
-does not contain mitochondria or chloroplast

Question 9

Magnification equation

Answer 9

Magnification=image size divide by real size

Question 10

A specimen is 50 micrometers wide.Calculate the width of the image of the specimen under a magnification of x100.Give answer in mm

Answer 10

Image size=100x50
5000=micrometer
5=mm

Question 11

Microscopy practical

Answer 11

Look at cgp book page 13

Question 12

Cell differentiation is?

Answer 12

Is the process by which a cell changes to become specialised for its job

Question 13

Why do cells differentiate?

Answer 13

As cells change they develop different subcellular structures and turn into different types of cells which allows them to carry out specific functions.

Question 14

What are cells that are undifferentiated called?

Answer 14

Stem cells

Question 15

One example of a specialised cell

Answer 15

Sperm cell-is to carry the male DNA to the female DNA.Function is it has long tail and streamlined head to swim quickly and have a lot of mitochondria for energy

Question 16

Specialised cells

Answer 16

Nerve cell,muscle cells ,root hair cell ,phloem and xylem cells
Look in cgp book 14

Question 17

Chromosomes contain what information and what are they?

Answer 17

Contain genetic information
-most cells in your body have a nucleus that contains genetic material in the form of chromosomes and are coiled up lengths of DNA molecules

Question 18

How many chromosomes does a person have?

Answer 18

46 chromosomes in total
23 from each parent

Question 19

Growth and DNA replication

Answer 19

1)in a cell that not dividing the FNA is all spread out in long strips
2)before it divides the cell has to grow and increase
3)then duplicates its DNA

Question 20

Mitosis

Answer 20

4)the chromosomes line up at the centre of the cell and cell fibres pull them apart.The two arms of each chromosome go to opposite ends of the cell
5)membranes form around each of the sets of chromosomes, these become nuclei of the two new cells-nucleus is divided
6)Lastly the cytoplasm and cell membrane divide.the cell has now produced two new daughter cells-they contain same DNA

Question 21

Stem cells

Answer 21

Check page16 cgp

Question 22

What is diffusion?

Answer 22

The spreading out of particles from an area of higher concentration to and area of low concentration

Question 23

How to speed up the rate of diffusion?

Answer 23

Bigger concentration gradient
Higher temperature because they have more energy to move around faster

Question 24

What’s the clever thing about cell membrane?

Answer 24

Don’t actually allow what goes in and out of the cell but really the substances can move in an out of cells through diffusion.

Question 25

What can fit through the gaps of the cell membrane?

Answer 25

Oxygen,water,amino acid and glucose

Question 26

What can’t?

Answer 26

Protein and starch

Question 27

Osmosis is what

Answer 27

The diffusion of water molecules from an area of higher water concentration to and area of low water concentration

Question 28

What’s a partially permeable membrane?

Answer 28

It’s just one with very small holes in that only water molecules can fit through and bigger molecules like sucrose can’t

Question 29

What happens when there is to much water on one side of the net flow?

Answer 29

There is more water on one side that on the other, there is a steady net flow of water into the region with fewer water molecules into the stronger sugar solution meaning the strong solution gets more dilute and the water tries to even up the concentration on either sides of the membrane

Question 30

What’s active transport?

Answer 30

When the concentration gradient is the wrong way around causing it to go from an area of low concentration to and area of high concentration

Question 31

Where’s active transport found?

Answer 31

Root hair cells and gut

Question 32

Describe a root hair cell

Answer 32

1)The cells on a plant root grow hairs which stick out into the soil 2)Each branch of root will be covered in millions of these microscopic hairs 3)This gives the plant a large surface area for absorbing water and mineral ions from the soil 4)Plants need these mineral ions for healthy growth 5)The concentration of minerals is usually higher in the root hair cells than in the soil around them

Question 33

How does a root hair cell take in minerals using active transport?

Answer 33

Active transport allows the plant to absorb minerals from a very dilute solution against a concentration gradient (very essential for its growth) but actuve transport needs energy from respiration

Question 34

What’s another example of active transport in humans?

Answer 34

In the gut there is a lower concentration gradient then in the blood stream meaning they have to use a process called active transport.This process allows nutrients with a lower concentration gradient to diffuse into the blood stream.

Question 35

An example of active transport happening inside the gut?

Answer 35

Glucose can be taken into the bloodstream when it’s concentration gradient is already higher that in the gut.

Question 36

Where does gas exchange take place?

Answer 36

Lungs

Question 37

How does the alveoli work?

Answer 37

-Air comes in through the nose and into the air sac (stays in the alveolus) -from that air oxygen diffuses into the blood capillary where red blood cell are found -then the co2 diffuses from the red blood cell to the alveolus and leaves the air sac.

Question 38

What are the air sacs in the lungs called?

Answer 38

Alveoli-where gas exchange takes place

Question 39

How is the alveoli specialised to maximise the diffusion of O2 and Co2?

Answer 39

-an enormous surface area -very thin walls -good blood supply

Question 40

Where is the villi found?

Answer 40

Small intestine

Question 41

What do they do?

Answer 41

They increase the surface area in a big way in order for that digested food to be absorbed much more quickly into the blood

Question 42

What happens when carbon dioxide diffuses into the air spaces?

Answer 42

Carbon dioxide diffuses into the air spaces within the leaf then it diffuses into the cells where photosynthesis takes place

Question 43

What’s the stomata?

Answer 43

Little holes which carbon dioxide diffuses in through

Question 44

What diffuses out from the stomata?

Answer 44

Oxygen and water vapour

Question 45

What are guard cells?

Answer 45

Controls the stomata

Question 46

Check more on page 22 cgp for the gills of a fish

Answer 46

More exchanging substances