B1 - Cells and cell processes

Question 1

Define nucleus

Answer 1

contains DNA that controls the activities of the cells

Question 2

Define cytoplasm

Answer 2

gel-like substance where most of the chemical reactions happen. It contains enzymes to control these chemical reactions

Question 3

Define cell membrane

Answer 3

holds the cell together and controls what goes in and out

Question 4

Red blood cells

Answer 4

concave (SA and pass smoothly through capillaries)
haemoglobin
no nucleus
mature RBC do not contain mitochondria

Question 5

Sperm and egg cells

Answer 5

when sperm fuses, eggs membrane changed to stop any more sperm getting in - right amount of DNA
sperm- mitochondria

Question 6

Four types of pathogen

Answer 6

fungi
protozoa
viruses
bacteria

Question 7

Describe bacteria

Answer 7

1/100th of body cell size
asexual reproduction by binary fission
make you feel ill by damaging your cells and producing toxins

Question 8

WBC

Answer 8

1) Ingestion

2) Antibodies - has antigens on surface, when foreign antigen, antibodies produce and lock on

Question 9

Example of strain that can’t be treated by antibiotics

Answer 9

MRSA causes serious wound infections and is resistant to methicillin

Question 10

Define gene

Answer 10

section of DNA that contains the instructions for one protein

Question 11

Optimum pH of enzymes in human body

Answer 11

37

Question 12

Enzyme that is suited to low pH

Answer 12

Pepsin breaks down proteins in stomach, pH2

Question 13

Anaerobic respiration reaction

Answer 13

glucose = lactic acid (+energy)

Question 14

How is glucose stored in the body?

Answer 14

as glycogen stored mainly in liver (but each muscle has its own store). When exercising, glycogen is converted back into glucose

Question 15

When is active transport used?

Answer 15

low concentration of nutrients in the gut, high concentration of nutrients in the blood - stops us starving

Question 16

Which molecules can fit though the membrane?

Answer 16

oxygen
glucose
amino acids
water

Question 17

Which molecules can’t fit through the membrane?

Answer 17

starch

proteins

Question 18

Define osmosis

Answer 18

The net movement of water molecules across a partially permeable membrane from a region of higher water concentration to a region of lower water concentration

Question 19

What is tissue fluid?

Answer 19

water with oxygen and glucose and other substances

Question 20

Osmosis experiment

Answer 20

potato cylinders with different concentrations of sugar solutions
measure lengths before and after