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Flashcards in SB1 Deck (39)
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1

What type of cells are animal cells?

Eukaryotic

2

What does eukaryotic mean?

Are membrane bound with a nucleus and cytoplasm.

3

What type of microscope must be used to view ribosomes?

An electron microscope.

4

What is the function of the cytoplasm?

A jelly-like material that contains dissolved nutrients and salts and structures called organelles. It's where many of the chemical reactions happen.

5

What is the function of the nucleus?

Contains genetic material,including DNA, which controls the cell's activities.

6

What is the function of the cell membrane?

It is permeable to some substances but not to others and so controls the movement of substances in an out of the cell.

7

What is the function of mitochondria?

Organelles that contain the enzymes for respiration, and where most energy is released in respiration.

8

What is the function of ribosomes?

Tiny structures where protein synthesis occurs.

9

What are most cells?

Specialised and adapted for their function. Animals and plants therefore consist of many different types of cells working together.

10

What are plants made up of?

Plant cells.

11

What are plant cells?

Eukaryotic.

12

What are the sub-cellular structures that animal and plant cells share?

The nucleus, cell membrane, mitochondria and ribosomes.

13

Name and describe the additional sub-cellular plant cell structures.

Chloroplast- organelle that contains the green pigment, chlorophyll, which absorbs light energy for photosynthesis. Contains the enzymes needed for photosynthesis.
Cell wall- Plant and bacterial cell walls provide structure and protection. Only plant cell walls are made from cellulose.
Permanent vacuole- Filled with cell sap to keep the cell swollen.

14

What are bacterial cells?

Unicellular and prokaryotic.

15

What does prokaryotic mean?

No nucleus so DNA roams free in the cytoplasm.

16

What might larger bacterial cells be visible under?

A light microscope.
An electron microscope would be needed to see the details of the cells organelles.

17

What components of a bacterial cell are unique to bacteria?

Chromosomal DNA- The DNA of bacterial cells is found loose in the cytoplasm. It is called chromosomal DNA and is not contained within a nucleus.
Plasmid DNA- Bacteria also have small, closed-closed-circles of DNA called plasmids present in their cytoplasm. Unlike the chromosomal DNA, plasmid DNA can move from one bacterium to another giving variation.
Flagella- Bacteria can have one or more flagella (singular: flagellum). These can rotate or move in a whip-like motion to move the bacterium.
Cell wall- Plant and bacterial cell walls provide structure and protection. Only plant cell walls are made from cellulose.

18

What happens in sexual reproduction?

In sexual reproduction. the nucleus of an egg cell fuses with the nucleus of a sperm cell to create a fertilised egg, which then develops into an embryo. Both the nucleus of a sperm and egg cell have 23 chromosomes which is half of the amount in a normal body cells- this is why they're called haploid.
This means that when they fuse, the fertilised egg has the full 46 chromosomes. It's then diploid.

19

How is an egg cell adapted to its function?

1) It contains nutrients in the cytoplasm to feed and nourish the embryo.
2) It has a haploid nucleus.
3) Straight after fertilisation, the cell membrane changes structure in order to prevent any other sperm from entering. This is so that the embryo has the right amount of DNA.

20

How is a sperm cell adapted to its function?

1) A sperm cell has a long tails so it can swim to the egg.
2) It has lots of mitochondria in the middle section so that it has lots of energy to swim the distance.
3) It also has an acrosome at the front of the 'head' . where it sores enzymes needed to digest its way through the membrane of the egg cell.
4) It also contains a haploid nucleus.

21

How is a cilia cell adapted to its function?

1) Epithelial cells line the surfaces of organs.
2) Some of them have cilia on top.
3) Cilia move substances as they beat in one direction to move the substances along the surface of the tissue.

22

What are the following in standard form:
mm
μm
nm
pm

mm = 1 x 10 to -3
μm = 1x 10 to -6
nm = 1 x 10 to -9
pm = 1 x 10 to -12

23

What is the equation that links magnification, image size and real size?

Mag = image/ real.

24

What is the equation for total magnification?

Eyepiece lens magnification x objective lens magnification.

25

How can you test for sugars using benedict's reagent?

1) Add Benedict's reagent to a sample and heat it in a water bath at 75 degrees. If the result is positive, a coloured precipitate will form.
2) The higher the concentration of reducing sugar. the further the colour change goes. (Blue= least to Red= most)

26

What is the starch test for iodine?

Just add iodine solution to the test sample.
1) If starch is present, the sample changes from browny-orange to bluey-black.
2) If no starch is present, the sample stays browny-orange.

27

What is the emulsion test for lipids?

1) Shake the test substance with ethanol for about a minute until it dissolves, then pour the solution into water.
2) If there are any lipids present, they will precipitate out of the liquid and show up as a milky emulsion.
3) The more lipid there is, the more noticeable the milky emulsion is.

28

What is Biuret's test for proteins?

1) First, add a few drops of potassium hydroxide solution to make the solution alkaline.
2) Then add some copper (II) sulfate solution (which is bright blue).
-If proteins are present, it will turn purple.
-If proteins aren't present, it will stay blue.

29

What does carbohydrase do?

Convert carbohydrates into simple sugars.

30

What does protease do?

Convert proteins into amino acids.