Year 10 biology

label the 3 components of the nucleotide shown below

phospate, nitrogenous base, deoxyribose sugar

a strand of DNW has the base sequence AAT GCG ATG CGA . state the base sequence for the complementary strand

TTA CGC TAC GCT

describe 4 differences between the structure or function of DNA and RNA

1. dna is double stranded, rna is single stranded

2. dna contains deoxyribose sugar, rna contains ribose sugar

3. dna has bases CGAT, rna has bases CGAU(rna has uracil instead of thymine)

4. dna is found in the nucleus and stays in the nucleus, rna can leave the nucleus and be found in the cytoplasm

explain the difference between a nitrogen base and a codon

a codon is a group of 3 nitrogenous bases

Explain whether a gene or a chromosome provides the most information about the genetic make-up of an individual

A single chromosome contains multiple genes. This means a chromosome provides a lot more information about the genetic make-up of an individual than a single gene.

1. State the total number of chromosomes shown.

2. State if child is male or female and justify answer

3. As the geneticist, advice the parents in the health of the baby

1. 47

2. Male since ir has an X and a Y chromosome

3. The child has 3 copies of chromosome 21, so does have a genetic condition. In this case, the condition would be Down Syndrome

1. Convert the following dna sequence into an rna sequence: CCG ATA CGC GGT ATT

2. State the amino acid sequence using the table above

3. Predict the effect on the protein strand if the SECOND A in the DNA sequence was misread as a T

1. GGC UAU GCG UAA

2. Glycine - Tyrosine - Alanine - Proline - “Stop” codon

3. This changes the RNA strand to UAA, which is a “stop” codon. This stops amino acid production at this point, reducing the length of the protein and possible affecting its function.

State the difference between transcription and translation

Transcription is the process of turning DNA into RNA (transcribing / copying it).

Translation is the process of forming amino acids from the RNA strand (translating bases into amino acids)

a. What Statement below is not a function of mitosis

A . Replenishing the epithelial cells of the small intestine that are shed daily.

B​. Forming new red blood cells to replace those that are worn out.

 C​. Forming cells for sexual reproduction.

D​. Repairing cuts and abrasions of the skin.

b. State the name given to the process responsible for the function u selected in (a)

c. Propose a reason why this process is not a function of mitosis. Consider what would happen if mitosis was responsible for this function

A. C

B. Meiosis

C. Mitosis produces daughter cells that are genetically identical to the parent, so have 2 sets of chromosomes. If sex cells are produced by mitosis, when fertilisation occurs the zygote will have 4 sets of chromosomes (for a total of 92). This would continue to double each generation.

State the difference between a halploid cell and a diploid cell

a haploid cell contains one set of chromosomes (n=1). sex cells r haploid cells.

a diploid cell contains two sets of chromosomes (n=2). body cells are all diploid cells

what is each stage of mitosis

1. interphase

2. prophase

3. metaphase

4. anaphase

5. telophase

6. cytokinesis

describe each stage of mitosis

1. interphase: chromosomes duplicate and the cell builds extra organelles. the normal life of a cell

2. prophase: the chromosomes duplicate to form bivalent chromosomes and chromosomes become visible. chromosomes appear, nucleus membrane disappears, spindle forms

3. metaphase: nuclear membrane disappears, and spindle fibres attach to chromosomes which line up at the equator. the chromosomes line up in a single line across the centre of cell

4. anaphase: the bivalent chromosomes split into sister chromatids, which r each pulled to the opposite side of the cell by spindle fibres. each side receives one chromatid per pair and a set of organelles.

5. telophase: the cell begins splitting into two new cells, each containing 46 chromosomes. nuclear membranes re-form

6. cytokinesis: the new cell wall forms, separating the two new cells from each other. cytoplasm divides; two daughter cells are produced

describe the difference between autosome and sex chromosome

sex chrosomed determine the sex of an individual. autosomes r all the chromosomes that aren’t sex chromosomes

determine the different between a gene and allele

an allele is a variation/possible version of a gene

describe the difference between heterozygous and homozygous

an individual is heterozygous for a trait if they have two different alleles for a trait. an individual is homozygous for a trait if they have two of the same alleles for a trait

define a genotype and provide an example

the allele combination an individual carries for a trait, for example Rr

define phenotype and provide an example of each

the observable characteristics of a trait, for example can roll tongue

patate the conditions under which dominant traits r expressed. contrast this to the conditions under which recessive traits r expressed.

dominant traits wil be expressed whenever there’s at least one copy of the dominant allele present.

recessive traits will only be expressed if they’re the only allele present

attached earlobes (E) is dominant to unattached earlobes. write the possible genotypes for

a. attached earlobes

b. unattached earlobes

c. carriers

a. EE and Ee

b. ee

c. Ee

long eyelashes (L) r dominant to short eyelashes. a woman and man, both with long lashes, have 2 children. the daughter has long lashes and the son has short. write the possible genotypes for each individual.

woman:

man:

daughter:

son:

Ll

Ll

LL or Ll

ll

state how a sex linked trait is different to an autosomal trait

a sex linked trait is found in the sex chromosome instead of an autosome

list 4 conditions that r sex linked

haemophilia, red green colour blindness, high blood pressure, muscular dystrophy

what’s a square, circle, coloured square, coloured circle

male, female, affected male, affected female

if affected children always have affected parents, what’s the pattern of inheritance of the characteristic

sex-linked dominant

mendels laws of inheritance

• law of segregation: traits exist in pairs which must be separated before they’re passed onto offspring

• law of independent assortment: traits r inherited separately from eachother

• law of dominance: where an organism has 2 alternative forms of a gene, the dominant one will always be expressed

define genome

entire dna code of an individual

define dna

DeoxyriboNucleic Acid. a molecule that carries the genetic instructions essential for life

define nucleotides

basic units of dna made from sugar phosphate group and one nitrogenous base

define nitrogenous base

organic, nitrogen containing molecules in dna that pair in specific ways

describe what a dna molecule looks like

what r bivalent chromosomes

they have 2 identical strands. they’re formed during dna replication. each strand is called a chromatid, the 2 chromatically r bind at the centromere (middle of x chromosome)

how many chromosomes does humans have

46(unless abnormality) half from each parent

define protein

complex molecule essential for cellular functions and the foundation of genetic traits

define amino acid

a building block of proteins

define codon

sequences of 3 nucleotides

shape, location, nucleotides, and role of DNA

shape: deoxyribose sugar backbone, double stranded helix

location: nucleus

nucleotides: A T G C

role: stores genetic info as instructions to be copied into mRNA and actioned

shape, location, nucleotides. and role of mRNA

shape: ribose sugar backbone, single strand of nucleotide codons

location: nucleus

nucleotides: A, uracil(U), G , C

role: messenger, carries info from dna gene code to ribosomes

shape location nucleotides and role of tRNA

shape: cloverleaf with anticodon , amino acid attached

location: cytoplasm

nucleotides: U,A,G,C

role: transfer, transfers amino acids to ribosome so they can be added to the protein chain in order

define mitosis

process of cell division to provide growth or repair

define meiosis

the process rhag results in the formation of gamete’s with half the genetic material of the parent cell

define gamete

sex cell(sperm or egg/ova) that has the genetic material of the parent cell

draw a labelled diagram of mitosis

define alleles

a version of a gene

define autosome

a non sex chromosome (1-22)

define sec chromosome

directly involved with determining sex. X and Y in humans

7 features of mitosis

• produces w des

• undergoes PMAT phases

• dna replication occurs prior to division

• cytokinesis separates new cells

• one cell division occurs

• two identical daughter cells

• formation of diploid somatic cells

7 featurez of meiosis

• produces new cells

• undergoes PMAT phases

• dna replication occurs prior to division

• cytokinesis separates new cells

• two cell divisions occur

• four genetically difference daughter cells

• formation of haploid gamete cells

state the 4 patterns of inheritance

autosomal dominant, autosomal recessive, x linked dominant, x linked recessive

describe autosomal dominant

• typically appears in every gen

• unaffected individuals don’t transmit the trait; affected individuals must have at least one affected parent

• make and female equally likely to inherit trait

describe autosomal recessive

• trait often skips a gen

• unaffected individuals may transmit trait; affected individuals don’t have to have an affected parent

x linked/ sex linked recessive

• trait can skip a generation

• more common in males

• affected father can’t pass trait to son

• only females can be carriers

x linked / sex linked dominant

• affected males pass trait to all daughters but no sons

• affected females can pass trait to both sexes with: one allele 50% chance (heterozygous), two alleles 100% chance (homozygous)

• appears in every generation

how many chromosomes does a human gamete have

they’re haploid cells thag contain 23 chromosomes