biology topic 3+4 H

Question 1

why is the plasma membrane called the fluid mosaic model

Answer 1

Fluid becuase molecules are free moving

mosaic because proteins are present

Question 2

give similarities/ differences between mitosis and binary fission

Answer 2

mitosis:
-linear DNA
-only in eukaryotic cells
-produces 2 daughter cells

binary fission:
-circular DNA
-only in prokaryotic cells
-produces 2 daughter cells

Question 3

list functions of proteins in the plasma membrane

Answer 3

-enzymes
-active transport of molecules across the membrane
-carrier proteins
-receptors

Question 4

Why do you soak the root tips in HCL in root tip squash practical

Answer 4

Breaks the cell wall so cells can be squashed easier /stain get in

Question 5

How does pressing the cover slip down on the cells in root tip squash help see mitosis

Answer 5

Cover slip will squash the membrane-bound organelles so they’re a single layer and light can pass through

Question 6

What happens during prophase

Answer 6

DNA condenses, chromosomes become visible and nuclear membrane breaks down

Question 7

What happens during metaphase

Answer 7

The chromosomes form a line on the equator of the cell

Question 8

What happens during anaphase

Answer 8

The sister chromartids pull away from each other and are pulled to the poles of the cell

Question 9

What happens during telophase

Answer 9

Chromosomes condense the spindle breaks down and nuclear membranes reform

Question 10

Give reasons for different results in root tip squash experiment

Answer 10

-Using different fields of view in the microscope
-looked at different parts of the root tip

Question 11

Give features of facilitated diffusion

Answer 11

-doesn’t use ATP
-uses carrier/ channel proteins
-goes down concentration gradient

Question 12

Give features of active transport

Answer 12

-uses ATP
-uses carrier proteins
-goes against the concentration gradient

Question 13

Explain why adding a susbatance that inhibits respiration will slo down rate of ion uptake

Answer 13

Because the cell will use diffusion which is slower than ATP

Question 14

Explain why a respiratory inhibitor stops absorbtion of amino acids

Answer 14

-stops ATP from being produced
-no sodium comes out the cell into the blood
-no concentration gradient for sodium to move into the cell

Question 15

Why is it important to control how much water is in each cell in the beetroot disc experiment

Answer 15

-water will make the pigment look light and therefore increase the transmission
-only want temperature as independent variable
-

Question 16

How does increasing temperature increase amount of pigment during beetroot disc experiment

Answer 16

Damages the cell membrane which damages the phospholipid bilayer