Unit 4a Study Guide Flashcards
Differentiate between somatic cells & germ cells
-Somatic- body cells, made up of most of your body tissues and organs
-Germ- Found in reproductive organs, develop into gametes, DNA can be passed onto offspring
How many chromosomes are contained in human somatic cells?
46
Name the male gamete
Sperm cells
what is the term for female gamete?
Ova (eggs)
How many chromosomes are contained in a human gamete?
23
What are homologous chromosomes?
Has the same genes but a different code
What gender is a person whose nuclei contain one x and one y chromosomes? (XY)
Male
What gender is a person whose nuclei contain two x chromosomes? (XX)
Female
Which contains MORE genes- an x chromosomes or a y chromosome?
X Chromosome
What is the term for the fusion of an egg cell & a sperm cell?
Fertilization
Differentiate between diploid (2n) & haploid (n) cells
Diploid (2n)- has two copies of each chromosomes while haploid (n) has only one copy
Are somatic cells diploid or haploid?
Diploid
Why is it important that gametes are haploid?
When the sperm and egg cell fuse together, the cell will have 46 chromosomes
What type of division does germ cells undergo in order to produce gametes?
Miosis
How many cells are produced by mitosis?
2
How many cells are produced by meiosis
4
What is gametogenesis?
Production of gametes
What are polar bodies?
One of the four cells produced by meiosis will become an egg. The egg will receive most of the organelles. The other cells will go on to become polar bodies
Why is genetic variation a good thing for a species?
Helps them adapt to new environments or survive
what happens when crossing over occurs during meiosis?
Exchange of chromosome segments between homologous chromosomes during prophase 1 of meiosis 1. This results in recombination
What is gene linkage?
Genes located close together can be inherited together
What stage must happen before humans are able to reproduce?
Puberty
Where are the human egg cells produced?
Ovaries
What is the main female hormone that controls reproduction?
Estrogen
What happens to a human egg once it leaves and ovary?
Enters the fallopian tube
In what organ will a fertilized egg develop into a baby?
Uterus
Where are human sperm produced?
Testicles
What is the main male hormone that controls reproduction?
Testosterone
What is the term for that cell that forms when an egg and sperm unites?
Zygote
What is the name for the fluid-filled sac that protects a developing embryo?
Amniotic sac
What is the role of the placenta?
Connects the mother and the embryo, allowing the exchange of oxygen, nutrients, and waste
How are the embryo & the placenta connected?
Umbilical cord
A human pregnancy typically last about ___ months
9
What are the three major stages of a human pregnancy called?
Trimesters
Why is it challenging for scientist to study DNA?
While DNA is a large molecule its far too small to see
what do scientist use to cut up DNA into manageable sections?
Enzymes
What is a restriction map?
DNA fingerprint
what is a polymerase chain reaction (PCR)?
Technique that produces millions-billions of copies of a specific DNA sequence in just a few hours
List three great uses for DNA fingerprinting
-Solving crimes
-Prove family relationships
-Identify genetically engineered crops
What is a clone?
Genetically identical copy of a gene or an entire organism
Why are bacteria that reproduced via binary fission clones of each other?
Exact same DNA
What are some issues associated with the cloning of mammals?
-Unhealthy
-Age quickly
-Environmental factors
Why is genetic engineering possible?
All organism share the same basic nucleotides
What is recombinant DNA?
DNA that contains genes from more than one organism
What does it mean when a organism is transgenic?
Organism that has one of more genes from another organism inserted in its genome
What are some issues that many people have with genetically modified (GM) plants?
-Not enough research
-some genes can cause allergic reactions
-Consequences to the environment
-Genetic diversity is decreased
What is a genome?
All organisms genetic information
What is genomics?
Study of genomes
what is the purpose of the Human Genome project?
It mapped and sequenced all the DNA base pairs of human chromosomes. It identified all genes within a sequence
Why is genetic screening sometimes controversial?
-People become anxious
-False positives or false negatives
-Risk of social stigmatization
-Privacy issues
What occurs when a person undergoes gene therapy?
The replacement of a defective or missing gene or the addition of a new gene into a persons genome to treat a disease
