Biology Study Guide

Biology Study Guide

crossing over

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**Which event is an important factor in increasing variety among sexually reproducing organisms?** 

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produces haploid gametes

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**Which phrase best describes the process of meiosis?** 

acts as a source of variations within a species never occur

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**The exchange of segments of DNA between the members of a pair of chromosomes __________.** 

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Pairs of homologous chromosomes exchange segments.

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**Which phrase best describes the process of crossing over?** 

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Males produce four functional sperm while females produce only one functional egg.

**How is gametogenesis different in females than in males?**

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meiosis I

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**During which of these does the separation of homologous chromosomes occur?**

**A.** mitosis **B.** meiosis I

**C.** meiosis II **D.** fertilization

exchange corresponding segments of DNA

**What happens to chromosomes when crossing over takes place?** 

They are divided.

**What happens to the sister chromatids in meiosis II?** 

anaphase I

**In which phase of meiosis does the chromosome number change from diploid to haploid?**

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division of homologous chromosomes

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**Which phrase best describes meiosis I?** 

False

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**True/False**: Meiosis begins with haploid cells and ends with diploid cells

True

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 **True/False**: Meiosis has two cell division stages

False

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**True/False**: Meiosis II divides the sister chromatids into four haploid cells

False

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**True/False**: Crossing Over takes place in Telophase II of meiosis

True

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**True/False:** All gametes formed at the end of meiosis are haploid

True

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**True/False:** A zygote formed from the process of fertilization is a diploid cell

True

 **True/False:** Random alignment results in chromosomes that have different combinations of alleles than they had before. 

True

 **True or False?** The diploid cell that enters meiosis becomes 4 haploid cells at the end of meiosis.

Doubles then divide in half.

 **During meiosis, chromosome number** 

Two of the above

 **During meiosis I,** 

a. Homologous chromosomes separate. 

b. Each sister chromatid becomes a chromosome. 

c. Sister chromatids separate. 

d. 4 daughter cells are formed from a single original cell. 

e. Two of the above. 

A

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**Which of these cells is shown during metaphase I of meiosis?**

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Late Prophase I and Early Metaphase I

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 **During meiosis, when does crossing over occur?** 

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 Sister chromatids separate.

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 **Which of the following happens during both meiosis and mitosis?** 

a. Crossing over 

b. Random alignment of homologous chromosomes 

c. Sister chromatids separate.

d. Homologous chromosomes separate

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Sperm and egg

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 **Which cells are formed by meiosis?**

One

 **A human female forms how many eggs from one original cell?**

46

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 **How many total chromosomes are there in the karyotype of a normal human?**

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interphase   

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 **The division of sex cells is known as** 

interphase

**During which stage of the cell cycle does the cell grow, the DNA replicates, and the organelles are copied?**

More than 46 chromosomes, miscarriage, male, multiple trisomies (3 chromosomes in a pair), This karyotype resulted from nondisjunction of an entire cell, The haploid number of this person is over 34.

What does the picture indicate?

Diploid number 46, Haploid number 23, 23 homologous pairs of chromosomes, 1 trisonomy, male, no birth defects

What does the picture indicate?

The age of an individual

**The karyotype can tell us about all of the following facts except ONE**

The gender of an individual The species the individual belongs

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The age of an individual The disorder the individual has

Down syndrome

**An individual was diagnosed with Trisomy 21 (extra chromosome in the 21st set), the patient is likely to have what type of syndrome**

Patau syndrome

 **An individual was diagnosed with Trisomy 13 (extra chromosome in the 13th set), the patient is likely to have what type of syndrome**

Down Syndrome

**An individual was diagnosed with Trisomy 21 (extra chromosome in the 21st set), the patient is likely to have what type of syndrome**

autosomes are arranged from largest to smallest

**In karyograms, _______.**

Metaphase II

**Which stage of meiosis II is the cell in?**

karyotype

**A picture that shows all of a cell's chromosomes, matched up into pairs is called a ________.**

female, male

 **If a person's sex-determining chromosomes consist of two X chromosomes (XX), that person is ________, whereas if they consist of an X and a Y (XY), that person is ________.**

gametes

**Sex cells are also termed ________.**

fertilization, a zygote

**When a sperm cell unites with an ovum (egg), it is called ______ and leads to the formation of ______.**

both parents

**Offspring born through sexual reproduction receive genes from ________.**

True

**In humans and most other animals, meiosis occurs in the testes of females and in the ovaries of males.**

False

**Meiosis reduces the number of chromosomes within a cell by one-half.**

stomata cells and somatic cells

**Body cells are also called ________.**

2

**Humans contain how many sex chromosomes.**

diploid (or 2n)

 **A cell containing the full complement of chromosomes is said to be a ________ cell.**

haploid (1n)

**A cell containing one-half of the normal complement of chromosomes is said to be a ________ cell.**

True

**In meiosis, two nuclear divisions yield a total of 4 haploid cells.**

tetrad

**Synapse forms a chromosome complex known as a ________.**

increases genetic diversity

**Crossing over ________**

when homologous chromosomes are paired up

**If crossing over occurs, it occurs ________.**

sister chromatids

**The two chromatids making up a chromosome are ________.**

non-sister chromatids

**Chromatids found on different chromosomes in a homologous pair are _________.**

non-sister chromatids

During crossing over, ________ exchange portions of DNA.

that carries DNA from both parents

**Crossing over results in a chromosome ________.**

microtubules that form spindles

**Extending from the centrioles are ________.**

False

**In meiosis I, all stages come to a clear stop before the cell enters the next stage.**

each chromosome in the homologous pair becomes attached to a different centriole

**At the start of metaphase I, ________.**

metaphase plate

**At the end of metaphase I, all chromosomes have been aligned at the equator of the cell, known as the ________.**

move towards different centrioles

**In anaphase I, chromosomes in the homologous pair _________.**

briefly move to the outside of the cell

**In telophase I, the spindles ________.**

1n

**At the end of telophase I, each pole of the cell is ________.**

double helix

**Which of the following best describes a DNA molecule?**

A. double helix             B.    contains ribose

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C. made of amino acids D.    contains Uracil

nucleotides

**Which of the following units are repeatedly joined together to form a strand of DNA?**

it serves as the blueprint for traits of all living things

**Why is DNA important?**

deoxyribose sugar and phosphate

**Which 2 molecules form the sides (backbone) of the DNA ladder?**

hydrogen bonds

**Nitrogenous bases are joined by which type of bond?**

sugar, phosphate, nitrogen base

**What are the three components of a nucleotide?**

Single Strand

**RNA is**

A-T and C-G

**Base pair for DNA is**

U-A and C-G

**Base pair for RNA is**

Transcription

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DNA-RNA-protein

**Genetic info flows in one direction. Which best represents this flow?**

5’-TACGGTA-3’

**What is the complementary base pair to the DNA strand below:**  5'-ATGCCAT-3'

helicase

**Enzyme that unwinds the DNA**

DNA polymerase I

The enzyme that adds nucleotides to the newly synthesized strand of DNA

Hershey & Chase

**Experiment that radioactively labeled the proteins and DNA of bacteriophages to determine if DNA or protein was the transforming agent**

each one with one new strand and one original strand

**DNA replication results in two DNA molecules,**

32% cytosine, 32% adenine, 18% thymine

**If a DNA molecule is 18% Guanine which of the following is correct**

18% cytosine, 32% adenine, 32% thymine

32% cytosine, 18% adenine, 32% thymine

18% cytosine, 64% adenine, 64% thymine

32% cytosine, 32% adenine, 18% thymine

Nucleus              

Where does transcription occur in eukaryotic cells?

UAC

**What is the complementary tRNA anticodon to the following mRNA codon: AUG**

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**AUA GGC UGA**

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Transcribe the following DNA sequence: TAT GGC ACT

Met-Asn-Cys-Stop

**Translate the following RNA sequence:**  *AUG AAU UGU UGA*

UAG UUA GCA AUC

**What is the complementary RNA sequence for the following:** ATC AAT CGT TAG

Gly-Ala-His-His   

**What is the amino acid sequence for the following:** GGG GCA CAT CAC

Either insertion or deletion of a base.

A frameshift mutation could result from

complementary to the corresponding mRNA codon.

**The anticodon of a particular tRNA molecule is** 

Insertion

**Original: ATC CAT**

**Mutation: ATC GCAT**

**What mutation occurred?**

substitution

**What type of mutation has occurred here?** 

T-G-A-C-C-A

T-G-A-G-C-A

it allows a gene to be transcribed

**What does a promoter do?**

A stop codon would be inserted

In the mRNA sequence: AUGUGGAACAGAUAC, what would happen if in the last codon, Guanine was substituted with Cytosine?

mRNA 

**What product gets made at the end of the process pictured?**

Introns

**The segments of RNA that are cut out are called.**

Exon

**In RNA processing, the coding sequence that remains in the final mRNA.**

ribose

**RNA contains the sugar**

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**Which of the following is a base that is NOT contained in DNA?**


1.    Adenine                                                   B.     Thymine

C.     Uracil                                                        D.     Guanine

**Uracil**

mutation

**Permanent change in a cell's DNA**

Ribosomal RNA

**A type of RNA that associates with proteins to form ribosomes.; Intron**

Transfer RNA

**The type of RNA that transports amino acids to the ribosomes is called** 

RNA polymerase

An enzyme that regulates RNA synthesis