Untitled Flashcards Set

B17. INHERITANCE QUIZ CARDS

Question Answer

Define inheritance the transmission of genetic information from generation to generation

Define chromosome thread-like structure of DNA, carrying genetic information in the form of

genes

Define gene length of DNA that codes for a protein

Define allele a version of a gene

What chemical are genes made up of? DNA (deoxyribose nucleic acid)

What sex chromosomes does a male have? XY

What sex chromosomes does a female have? XX

Describe the inheritance of sex in humans

Define halpoid nucleus a nucleus containing a single set of unpaired chromosomes e.g. in gametes

Define diploid nucleus a nucleus containing two sets of chromosomes (one inherited from the

mother and one inherited from the father), e.g. in body cells

Are gametes haploid or diploid? haploid

Are body cells haploid or diploid? diploid - there is a pair of each type of chromosome

How many pairs of chromosomes are there in a

human diploid cell?

23 pairs (46 chromosomes in total)

What are proteins made of? amino acids

What determines the order of amino acids in a

protein?

the sequence of bases in a gene is the genetic code for putting together

amino acids in the correct order to make a specific protein

Where in a plant/animal cell is DNA found? In chromosomes in the nucleus

How does DNA control cell function? by controlling the production of proteins (some of which are enzymes),

antibodies and receptors

for neurotransmitters

If one strand of DNA is ATCCCCG, what is on the

complementary strand?

TAGGGGC (apples in trees - A binds to T. C binds to G)

Where in a cell does protein synthesis occur? ribosomes

Describe how a protein is made – the gene coding for the protein remains in the nucleus

– mRNA molecules carry a copy of the gene to the cytoplasm

– the mRNA passes through ribosomes

– the ribosome assembles amino acids into protein molecules

– the specific order of amino acids is determined by the sequence of bases in

the mRNA

How do cells become specialised? all body cells in an organism contain the same genes, but many genes in a

particular cell are not expressed because the cell only makes the specific

proteins it needs

Name 3 roles / functions of mitosis in growth, repair of damaged tissues, replacement of cells and asexual

reproduction

Define mitosis nuclear division giving rise to genetically identical cells

Chromosomes duplicate BEFORE the start of

mitosis. True or False?

True!

Made by Cattaystudies

Made by Cattaystudies

What are the products of mitosis? Two genetically identical daughter cells (i.e. same number of chromosomes as

the parent cell)

Explain how during mitosis the number of

chromosomes is maintained between the parent

cell and daughter cell

the copies of the chromosomes separate, maintaining the

chromosome number (the parent cell and each daughter cell have the same

number of chromosomes)

If a cell has 48 chromosomes, and undergoes

mitosis, how many chromosomes will it have?

48

If a cell has 48 chromosomes, and undergoes

meiosis, how many chromosomes will it have?

24 (=half 48!)

Draw a diagram to show mitosis occurring

Define stem cells unspecialised cells that divide by mitosis to produce daughter cells that can

become specialised for specific functions

Define meiosis nuclear division that is reduction division in which the chromosome number is

halved from diploid to haploid in cells

List differences between mitosis and meiosis Mitosis - one division, same number of chromosomes in parent and daughter

cells, daughter cells are geneticlaly identical to parent cells, two daughter cells

formed

Meiosis - two divisions, half the number of chromosomes in daughter cell

than parent cell, daughter cells genetically different to parent cells, four

daughter cells formed

What is the function of meiosis Produce gametes with half the number of chromosomes of the parent cell

Draw a diagram to show meiosis occurring

How does meiosis produce variation? Cells contain new combinations of maternal and paternal chromosomes

Define genotype the genetic make-up of an organism in terms of the alleles present

Define phenotype the observable features of an organism

Define homozygous having two identical alleles of a particular gene

Made by Cattaystudies

Made by Cattaystudies

What is pure breeding? two identical homozygous individuals that breed together

Define heterozygous having two different alleles of a particular gene

If two heterozygous individuals are bred, is this

pure-breeding?

No (two homozygous individuals only)

If one homozygous and one hetereozygous

individual is bred is this pure-breeding?

No (two homozygous individuals only)

Define dominant an allele that is expressed if it is present

Define recessive an allele that is only expressed when there is no dominant allele of the gene

present

Explain how to use a test cross to identify an

unknown genotype

A test cross allows you to work out the genotype of an unknown parent.

You always cross the unknown parent with a homozygous recessive parent.

By looking at the offspring we can determine the genotype of the unknown

parent.

What does co-dominance mean? If both alleles are present, then they are both expressed

Give an example of co-dominance A & B in blood types

Explain what is meant by codominance and give an

example [3]

When for two (or more) alleles, both alleles are expressed in a heterozygous

individual. An example is AB blood group. Neither allele is dominant or

recessive

If one parent is IAIO and one is IBIO, what is the

chance the child will be blood group AB? Draw the

punnett square, list the genotypes and phenotypes

Genotypes:

25% IAIB, 25% IAIO

25% IBIO, 25% IOIO

Phenotypes:

25% AB, 25% A

25% B, 25% O

Answer = 25% chance AB

If one parent is IAIO and one is IBIO, what is the

chance the child will be blood group O? Draw the

punnett square, list the genotypes and phenotypes

Genotypes:

25% IAIB, 25% IAIO

25% IBIO, 25% IOIO

Phenotypes:

25% AB, 25% A

25% B, 25% O

Answer = 25% chance O

Define sex-linked characteristic a characteristic in which the gene responsible is located on a sex chromosome

and that this makes it more common in one sex than in the other

Name an example of sex linkage colour-blindness (the gene is located on the X chromosome, and because

there is no homologous region on the Y chromosome it is more prevalent in

males)

Why is it important for gametes to be haploid? So chromosome number does not double at fertilisation

So chromosome number remains constant from generation to generation

Discuss whether sickle cell trait is an example of

codominance [2]

Yes, because both alleles are expressed and there are 3 phenotypes

Explain why it is important that meiosis occurs

during the production of gametes. [2]

Meiosis produces genetically diffferent haploid cells so it contains half the

number of chromosomes and gives variation. This prevents the number of

chromosomes from doubling each generation.

Explain why genotypes of the seeds are not all the

same [2]

The gametes are different and produced by meiosis that gives rise to

variation. The pollen grains are collected by different plants