Modern Genetics Chapter 25 Flashcards

Questions and Answers

What are genes composed of?

DNA

Name two processes that DNA is responsible for.

Passing genetic information from generation to generation, DNA controls the manufacture of enzymes.

What is the long chain of units that make up a DNA molecule?

nucleotides

What are the four different nitrogenous bases of DNA?

adenine, thymine, guanine, and cytosine Signup and view all the answers

What is the sugar in DNA?

Deoxyribose Signup and view all the answers

What is the sugar in RNA?

Ribose Signup and view all the answers

What does the phosphate group in DNA nucleotides contain?

Phosphorus and oxygen Signup and view all the answers

According to Watson and Crick, DNA molecules are shaped like a?

Twisted ladder Signup and view all the answers

What is the twisted ladder structure of DNA called?

Double helix Signup and view all the answers

How are nitrogen bases attached to each other in a DNA molecule?

Weak hydrogen bonds Signup and view all the answers

According to the rule for DNA base pairing, which bases may be paired together?

adenine (A) with thymine (T), guanine (G) with cytosine (C) Signup and view all the answers

Why are daughter cells identical to parent cells after reproduction?

DNA makes exact copies of itself (replicates) Signup and view all the answers

What is it called when DNA makes exact copies of itself?

Replicates Signup and view all the answers

When does DNA replication occur?

During both meiosis and mitosis Signup and view all the answers

RNA contains the nitrogen base ________________________ instead of thymine.

Uracil Signup and view all the answers

One difference between DNA and RNA is that: DNA is __-stranded, while RNA is -stranded.

double, single Signup and view all the answers

Name the three kinds of RNA.

Messenger RNA (mRNA), Transfer RNA (tRNA), Ribosomal RNA (rRNA) Signup and view all the answers

Mutations result from abnormal sequences of?

Nucleotide bases Signup and view all the answers

What is the relationship between proteins and DNA?

DNA holds the code that is needed to make protein Signup and view all the answers

Traits are encoded in what parts of DNA?

In the bases of DNA molecules Signup and view all the answers

If traits are similar, so are?

Proteins Signup and view all the answers

The separation of DNA occurs at weak?

Hydrogen bonds Signup and view all the answers

Separation of DNA leads to its?

Replication Signup and view all the answers

What is the base pairing rule?

A-T, C-G Signup and view all the answers

DNA of parents should be similar to their?

Offspring Signup and view all the answers

Chromosomes are made of?

DNA Signup and view all the answers

Genes are determined by the _________ of molecular bases.

Sequence Signup and view all the answers

What does the sequence of bases determine?

Genes or traits Signup and view all the answers

The base sequence also determines the production of _ or _.

Proteins or enzymes Signup and view all the answers

Proteins are made from _ put together in a certain at the ___.

amino acids, sequence, ribosome Signup and view all the answers

Why are X rays dangerous?

They may alter base sequence Signup and view all the answers

Put in order from largest to smallest: chromosome, nucleus, gene.

Nucleus, chromosome, gene Signup and view all the answers

Why do siblings look alike?

Similar DNA that comes from both parents Signup and view all the answers

When does crossing over occur?

During meiosis Signup and view all the answers

What sex chromosomes do sperm carry?

X and Y Signup and view all the answers

What sex chromosomes do eggs carry?

X and X Signup and view all the answers

If a male has a genetic disease, how many sex chromosomes are affected?_ If a female has a genetic disease, how many chromosomes must be affected?

One (X), 2 (both Xs) Signup and view all the answers

What are the components of a nucleotide?

Deoxyribose sugar, phosphate, base Signup and view all the answers

What are the building blocks of DNA and RNA?

Nucleotides Signup and view all the answers

Put the following in order in terms of increasing size: DNA, nucleotide, nucleus, nucleotide base, chromosome.

Nucleotide base, nucleotide, DNA, chromosome, nucleus Signup and view all the answers

Individuality is determined by the ____________________ of DNA.

Base sequence Signup and view all the answers

What nucleotide pairs will 'unzip' in a DNA molecule?

A-T, G-C Signup and view all the answers

Study Notes

Genetics Overview

Genes consist of DNA, which is a chemical compound fundamental to heredity.
DNA passes genetic information across generations and controls enzyme production.

DNA Structure

DNA is composed of long chains of nucleotides.
The four nitrogenous bases in DNA are adenine (A), thymine (T), guanine (G), and cytosine (C).
The sugar component in DNA is deoxyribose, a 5-carbon sugar; RNA contains ribose.

Molecular Details

DNA nucleotides include a phosphate group made of phosphorus and oxygen.
Watson and Crick proposed that DNA has a twisted ladder structure known as a double helix.
The rungs of the ladder (nitrogen bases) are connected by weak hydrogen bonds.

Base Pairing Rules

Adenine pairs with thymine (A-T) and guanine pairs with cytosine (G-C).
In RNA, uracil (U) replaces thymine and pairs with adenine (A-U).

Cellular Processes

DNA undergoes replication, creating exact copies of itself during mitosis and meiosis.
Each daughter cell inherits identical DNA from the parent cell.

RNA Functionality

Three types of RNA are involved in protein synthesis: messenger RNA (mRNA), transfer RNA (tRNA), and ribosomal RNA (rRNA).
The sequence of nucleotide bases in DNA determines the genetic code for proteins and traits.

Genetic Stability and Variation

Mutations arise from changes in nucleotide sequences, potentially altering traits and protein production.
DNA from parents is similar to that of their offspring, reinforcing hereditary patterns.

Cellular Organization

Chromosomes, composed of DNA, contain genes determined by the sequence of molecular bases.
The hierarchy of genetic material from largest to smallest is: nucleus, chromosome, gene.

Reproduction and Traits

Siblings resemble each other due to shared DNA inherited from both parents.
Crossing over, which increases genetic diversity, occurs during meiosis.

Sex Chromosomes and Inheritance

Males have X and Y sex chromosomes, while females have two X chromosomes.
A male may show a recessive genetic disease if one X chromosome is affected; a female requires both X chromosomes to be affected.

Nucleotide Structure

A nucleotide comprises deoxyribose sugar, a phosphate group, and a nitrogenous base (A, T, C, or G).
Nucleotides are the fundamental building blocks of both DNA and RNA.

Genetic Size Scale

In increasing order of size: nucleotide base, nucleotide, DNA, chromosome, nucleus.

Individual Genetic Identity

Individual characteristics and traits stem from the unique base sequence of an individual's DNA.

Studying That Suits You

Use AI to generate personalized quizzes and flashcards to suit your learning preferences.

Description

Test your knowledge on the fundamental concepts of modern genetics with these flashcards. This quiz covers key terms and processes related to DNA, including its structure, functions, and importance in heredity. Perfect for students studying genetics and related fields.