1.2

Question 1

eukaryote

Answer 1

organism or cell which contains a nucleus and other organelles enclosed by a membrane

Question 2

eukaryotes have membranes. why are membranes important?

Answer 2

-provide a surface enzymes can attach on and chemical reactions can occur

-keep potential harmful chemicals or enzymes contained, stopping them from damaging/breaking down structures in the cell

-act as a transport system

Question 3

nucleus

Answer 3

-contains cell’s dna which provides the code for the synthesis of proteins

-the nuclear membrane encloses the nucleus. this double membrane contains gaps called nuclear pores.

-nuclear pores allow mRNA to exit the nucleus and travel to the cytoplasm.

-the interior of the nucleus contains a cytoplasm-like material known as the nucleoplasm containing cell’s dna in the form of chromatin.

-contains nucleolus which produces ribosomal RNA (rRNA)

Question 4

mitochondria

Answer 4

-release chemical energy in the form of ATP during aerobic respiration

-double membrane consists of an outer membrane, an intermembrane and inner membrane.

-inner membrane is folded to form the cristae. these folds increase surface area where ATP synthesis can occur.

-inside mitochondria is a matrix containing ribosomes and the mitochondrial DNA.

-mitochondrial DNA allows the mitochondria to divide to meet the cells needs. it is evidence that the mitochondria may of once been free living organisms that were ingested by the ancestors of eukaryote cells

Question 5

RER

Answer 5

-series of membranes that are linked to the nuclear membrane

-used as a transport system for proteins

-contains ribosomes which carry out protein synthesis

Question 6

SER

Answer 6

-series of membranes that do not have ribosomes on their surface

-involved in the synthesis of lipids

Question 7

ribosomes

Answer 7

-made up of protein and rRNA

Question 8

golgi body functions

Answer 8

-formation of glycoproteins and lysosomes

-modifying and packaging proteins to be exported from the cell

Question 9

how does the golgi body modify and package proteins?

Answer 9

-vesicles (small,membrane bound sacs) containing proteins formed by the RER fuse at one end of the golgi sacs

-the protein is modified inside the golgi sacs

-the modified protein is budded off in a vesicle at the other end of the golgi sacs

-the vesicle containing the modified protein travels to the cells outer plasma membrane where the protein is released by exocytosis

Question 10

lysosomes

Answer 10

-vesicles containing digestive enzymes

-used to break down worn out organelles and to digest material taken in by phagocytosis

Question 11

how do lysosomes carry out their function?

Answer 11

-material is taken into the cell and trapped in a vacuole

-lysosomes fuse with the membrane of the vacuole and release their digestive enzymes into the vacuole

-digestive enzymes break down the material

Question 12

centrioles

Answer 12

-small cylinders that separate from each other during the early stages of mitosis to form spindle fibres

Question 13

what are the three organelles with a double membrane?

Answer 13

nucleus, mitochondrion and chloroplast

Question 14

chloroplasts

Answer 14

-double membrane

-site of photosynthesis (process of sugars and organic molecules formed from CO2 and H2O using energy from sunlight)

-chloroplasts contain cytoplasm-like material called the stroma which contains starch grains, ribosomes and thylakoids.

-membrane of thylakoids contain the pigment chlorophyll, which absorbs the light energy used in photosynthesis.

-thylakoids form stacks called grana, which are linked by lamellae

-chloroplasts contain DNA which is evidence that chloroplasts were once free living organisms infested by the ancestors of plant cells

Question 15

plant cell wall

Answer 15

-made from cellulose

-keeps the plant cell rigid and prevents it from bursting

-contains pores called plasmodesmata which allow the cytoplasm of neighbouring cells to connect, enabling substances to pass between plant cells

Question 16

plant large permanent vacuole

Answer 16

-contains cell sap

-surrounded by membrane called tonoplast

-vacuole is used for storage and helps to support plant cell

-animal cells may also contain a vacuole but they are smaller and do not have a tonoplast

Question 17

prokaryote

Answer 17

single celled organism that has no nuclear membrane or any other membrane bound organelles

Question 18

prokaryote features

Answer 18

-capsule(outer layer)

-murein cell wall prevents cell from bursting

-mesosome is an infolding of the prokaryotes plasma membrane which increases surface area for respiration and other chemical reactions to occur

-dna is free in the cytoplasm or small circular pieces known as plasmids

-smaller ribosomes

-flagellum allows movement

Question 19

viruses

Answer 19

-contain no cytoplasm therefore not considered cells. generally thought not to be alive

-infect both prokaryotes and eukaryotes

-consist of nucleic acid and a protein coat

-in most viruses that infect eukaryotes, the nucleic acid is RNA, whereas in most viruses that infect prokaryotes, the nucleic acid is DNA

Question 20

tissue

Answer 20

-group of cells that have a similar structure and work together to form a particular function

-connective tissues e.g collagen, a structural tissue in animals

-xylem and phloem are plant tissues

Question 21

organs

Answer 21

-different tissues can combine to form organs, which carry out a common function

-roots and leaves are plant organs

Question 22

organ system

Answer 22

-made up of two or more organs working together to perform a life function

-such as the respiratory or digestive system in mammals

Question 23

magnification formula

Answer 23

image size/actual size