cells - lqc 1a

Question 1

which features do the cells of all living organisms share?

Answer 1

cell membrane, ribosomes, dna

Question 2

centrioles

Answer 2

Everv animal cell has one pair of centrioles, which are hollow cylinders made up of a ring of nine protein microtubules (polymers of globular proteins arranged in a helix to form a nollow tube. mey are involved in the formation of the spindle during nuclear division and in transport within the cell cytoplasm.

Question 3

mitochondria

Answer 3

The inner of its two membranes is folded to form finger-like projections called cristae. The mitochondria are the site of the later stages or aerobic respiration.

Question 4

nucleus

Answer 4

Enclosed by an envelope composed of two membranes perforated by pores. Contains chromosomes and a nucleolus. Chromosomes made of DNA contain genes that control the synthesis of proteins.

Question 5

nucleolus

Answer 5

A dense bodv within the nucleus where ribosomes are made.

Question 6

rough endoplasmic reticulum

Answer 6

A svstem of interconnected membrane-bound, flattened sacs. ribosomes are attatched to the outer surface
Proteins made on these ribosomes are transported through the
ER to other parts of the cell

Question 7

lysosome

Answer 7

spherical sacs containing digestive enzymes and bound by a single membrane. involved in the breakdown of unwanted structures within the cell, and in destruction of whole cells when old cells are to be replaced or during development. the acrosome is a specialised lysosome

Question 8

golgi apparatus

Answer 8

stacks of flattened, membrane bound sacs formed by fusion of vesicles from the ER. modifies proteins and packages them in vesicles for transport

Question 9

smooth endoplasmic retriculum

Answer 9

like rough ER but doesn’t have any attached ribosomes, smooth ER makes lipids and steroids

Question 10

ribosomes

Answer 10

Made of RNA and protein, these small organelles are found free in the cytoplasm or attached to endoplasmic reticulum. They are
the site of protein synthesis

Question 11

cell surface membrane

Answer 11

phospholipid bilayer contains proteins and other molecules forming a partially permeable barrier

Question 12

state 3 structural differences between a prokaryotic cell and a eukaryotic cell

Answer 12

· Prokaryotic cells have smaller ribosomes (70S) than eukaryotic cells (80S)
· Prokaryotic cells do not have membrane bound organelles, eukaryotic cells do eg. nucleus, mitochondria
· Prokaryotic cells have a circular chromosome, eukaryotic cells have linear chromosomes