Question

period: ____ date: ____________
6.5 exam review

1. two proteins in the same cell perform different functions. this is because the two proteins are composed of...

(1) chains folded the same way and the same sequence of simple sugars
(2) chains folded the same way and the same sequence of amino acids
(3) chains folded differently and a different sequence of simple sugars
(4) chains folded differently and a different sequence of amino acids

1. changing one base in a gene could have the most direct effect on the...

(1) function of the membrane of a cell
(2) sequence of building blocks of a protein found in a cell
(3) number of mitochondria in a cell
(4) type of carbohydrates synthesized by a cell

1. the diagram below represents levels of organization within a cell of a multicellular organism.

diagram of concentric circles labeled cell, nucleus, chromosome, and x
which statement is correct regarding the structure represented by x?
(1) structure x is composed of many different amino acids that determine the type of cell it will become in the organism.
(2) structure x is an arrangement of nucleotide bases.
(3) structure x is a folded chain arrangement of carbohydrates found in all the body cells of the organism.
(4) structure x contains 20 different kinds of subunits that are present in all the cells of the organism.

1. in a dna sample, 20% of the bases are thymine (t). what percentage of the bases in this sample are adenine (a)?

(1) 20% (3) 35%
(2) 30% (4) 70%

1. which diagram best represents the relative locations of the structures below?

a- chromosome b- nucleus c- cell d- gene
four diagrams of concentric circles with different labels
(1) diagram 1 (2) diagram 2 (3) diagram 3 (4) diagram 4

Explanation:

Question 1

Proteins are made of amino acids, and their function depends on their structure (folding) and amino acid sequence. Different functions mean different folding and amino acid sequences. Simple sugars are for carbohydrates, not proteins. So option (4) is correct as it has different folding and amino acid sequences.

Genes are DNA (nucleotide sequences) that code for proteins. A base change (mutation) in a gene affects the DNA sequence, which codes for the amino acid (building block of protein) sequence. Membrane function, mitochondria number, and carbohydrate type are not directly coded by a single gene base change. So option (2) is correct.

The diagram shows cell → nucleus → chromosome → X. Chromosomes have DNA, which is made of nucleotide bases. X is DNA (or gene - part of DNA). Amino acids are for proteins, carbohydrates are not in this structure, and 20 subunits (amino acids) don't apply here. So option (2) is correct as X (DNA) has nucleotide bases.

Answer:

(4) chains folded differently and a different sequence of amino acids

Question 2