B1 - Cells and cell processes Flashcards
Define nucleus
contains DNA that controls the activities of the cells
Define cytoplasm
gel-like substance where most of the chemical reactions happen. It contains enzymes to control these chemical reactions
Define cell membrane
holds the cell together and controls what goes in and out
Red blood cells
concave (SA and pass smoothly through capillaries)
haemoglobin
no nucleus
mature RBC do not contain mitochondria
Sperm and egg cells
when sperm fuses, eggs membrane changed to stop any more sperm getting in - right amount of DNA
sperm- mitochondria
Four types of pathogen
fungi
protozoa
viruses
bacteria
Describe bacteria
1/100th of body cell size
asexual reproduction by binary fission
make you feel ill by damaging your cells and producing toxins
WBC
1) Ingestion
2) Antibodies - has antigens on surface, when foreign antigen, antibodies produce and lock on
Example of strain that can’t be treated by antibiotics
MRSA causes serious wound infections and is resistant to methicillin
Define gene
section of DNA that contains the instructions for one protein
Optimum pH of enzymes in human body
37
Enzyme that is suited to low pH
Pepsin breaks down proteins in stomach, pH2
Anaerobic respiration reaction
glucose = lactic acid (+energy)
How is glucose stored in the body?
as glycogen stored mainly in liver (but each muscle has its own store). When exercising, glycogen is converted back into glucose
When is active transport used?
low concentration of nutrients in the gut, high concentration of nutrients in the blood - stops us starving
