Cell bio definitions

Question 1

prokaryotic cells

Answer 1

have no nucleus or membrane bound organelles, DNA is in an unbound region called the nucleoid

Question 2

eukaryotic cells

Answer 2

have a nucleus containing DNA and membrane bound organelles

Question 3

selective permeability

Answer 3

allows some substances to pass through more easily than others
e.g. plasma membrane

Question 4

passive transport (diffusion)

Answer 4

does not require ATP energy
movement from high to low concentration

Question 5

active transport

Answer 5

requires ATP energy
movement of molecules across a gradient

Question 6

osmosis

Answer 6

movement of water molecules from an area of high concentration to low concentration

Question 7

endocytosis

Answer 7

transport to the cell

Question 8

exocytosis

Answer 8

transport out of the cell

Question 9

autotrophs

Answer 9

make their own food
e.g. by photosynthesis

Question 10

heterotrophs

Answer 10

take in food made by the environment

Question 11

phagocytosis

Answer 11

the process by which a cell engulfs a particle and digests it

Question 12

somatic cells

Answer 12

have two sets of chromosomes (diploid)

Question 13

gene

Answer 13

a length of DNA that codes for a specific protein

Question 14

chromatin

Answer 14

material that makes up a chromosome that consists of DNA and protein

Question 15

nucleosome

Answer 15

segment of DNA wrapped around 8 histone proteins

Question 16

histons

Answer 16

major proteins in chromatin - packaging elements for the DNA