Search results for "Gene Editing"

Search Past Papers

Found 7 results

Biology

CAIE2024

(cid:44)(cid:1)(cid:1)(cid:1)(cid:1)(cid:9)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:9)(cid:44) (ii) Another method being investigated to treat LCA10 is to use a gene editing tool known as the CRISPR/Cas9 system. The CRISPR/Cas9 system uses a short length of RNA called guide RNA. Guide RNA is complementary to the target DNA and is linked to a nuclease enzyme called Cas9. Cas9 breaks phosphodiester bonds in DNA. The cell repair mechanisms repair the cut in DNA after the modification has taken place. • A vector delivers Cas9 and two specific guide RNAs to the photoreceptor cells. • They act on the section of DNA which contains the mutation. • Exon X is no longer added to the mRNA. Explain how this method used to treat LCA10 is an example of gene editing. ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ..................................................................................................................................... [3] [Total: 13] (cid:300)(cid:209)(cid:266)(cid:190)(cid:288)(cid:180)(cid:237)(cid:200)(cid:245)(cid:207)(cid:298)(cid:197)(cid:266)(cid:224)(cid:252)(cid:182)(cid:256)(cid:215) © UCLES 2024 (cid:300)(cid:224)(cid:201)(cid:241)(cid:214)(cid:300)(cid:253)(cid:297)(cid:234)(cid:263)(cid:239)(cid:191)(cid:183)(cid:203)(cid:296)(cid:259)(cid:269)(cid:258) 9700/42/O/N/24 (cid:293)(cid:277)(cid:181)(cid:277)(cid:181)(cid:277)(cid:261)(cid:277)(cid:213)(cid:245)(cid:261)(cid:261)(cid:261)(cid:245)(cid:261)(cid:277)(cid:213)(cid:213) NIGRAM SIHT NI ETIRW TON OD NIGRAM SIHT NI ETIRW TON OD NIGRAM SIHT NI ETIRW TON OD NIGRAM SIHT NI ETIRW TON OD NIGRAM SIHT NI ETIRW TON OD PMT * 0000800000009 *

Question

Biology

CAIE2024

(cid:44)(cid:1)(cid:1)(cid:1)(cid:1)(cid:9)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:6)(cid:44)

Question

Biology

CAIE2024

Phenotypic variation exists in natural populations. There are many causes of variation. Natural selection determines which phenotypes are advantageous. (a) Variation in a particular characteristic can be described as either discontinuouso r continuous. Table 5.1 contains a list of statements that apply to discontinuous variation, continuous variation or both. Complete both columns of Table 5.1. Put a tick (✓) in the box if the statement applies and leave the box empty if the statement does not apply. Table 5.1 statement discontinuous continuous variation variation often involves one gene only environmental factors may affect gene expression there is an additive effect of genes that contributes to the phenotype there are distinct differences between the various forms of a characteristic [4] © UCLES 2024 (cid:300) (cid:300) (cid:211) (cid:224) (cid:266) (cid:203) (cid:190) (cid:242) (cid:288) (cid:215) (cid:180) (cid:288) (cid:237) (cid:265) (cid:200) (cid:255) (cid:245) (cid:209) (cid:207) (cid:250) (cid:298) (cid:265) (cid:197) (cid:228) (cid:266) (cid:255) (cid:221) (cid:177) (cid:250) (cid:216) (cid:184) (cid:187) (cid:254) (cid:277) (cid:215) (cid:258) 9700/42/O/N/24 [Turn over (cid:293)(cid:197)(cid:229)(cid:277)(cid:245)(cid:245)(cid:197)(cid:245)(cid:293)(cid:181)(cid:213)(cid:197)(cid:261)(cid:181)(cid:293)(cid:213)(cid:245)(cid:213) NIGRAM SIHT NI ETIRW TON OD NIGRAM SIHT NI ETIRW TON OD NIGRAM SIHT NI ETIRW TON OD NIGRAM SIHT NI ETIRW TON OD NIGRAM SIHT NI ETIRW TON OD PMT * 0000800000012 *

Question

Biology

CAIE2024

Question

Biology

CAIE2022

(c) Some zoos use assisted reproduction techniques, such as embryo transfer, in their captive breeding programmes for endangered species. Embryo transfer has resulted in domesticated dromedary camels giving birth to wild Bactrian camel calves. Describe the procedure of embryo transfer in a mammal such as a camel. ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ............................................................................................................................................. [4] [Total: 9] © UCLES 2022 9700/43/O/N/22 [Turn over PMT

Question

Biology

CAIE2022

(ii) Explain why a promoter has to be transferred as well as the desired gene. ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ..................................................................................................................................... [2] (iii) A modified retrovirus is used to insert the new gene into the DNA of the blood stem cells. State two ethical considerations of using a retrovirus for gene therapy. ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ..................................................................................................................................... [2] (c) The gene therapy technique used to cure ADA-SCID is not suitable for treating the genetic disease called Huntington’s disease. A newer technique called gene editing could potentially be used instead to cure Huntington’s disease. Explain why gene editing is more suitable as a potential cure for Huntington’s disease. ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ............................................................................................................................................. [3] [Total: 13] © UCLES 2022 9700/43/O/N/22 [Turn over PMT

Question

Biology

CAIE2022

(a) The results of investigations carried out on mitochondria show how the structure of a mitochondrion is related to its role in aerobic respiration. • Intact mitochondria (not damaged) were removed from cells. • A technique was used to remove the outer mitochondrial membrane, leaving the inner membrane intact. • The inner mitochondrial membrane was separated from the contents of the matrix so that both could be analysed. (i) The removal of the outer membranes of mitochondria involves placing the organelles in pure water. This results in the rupture (bursting) of the outer membrane. The inner mitochondrial membrane does not rupture and remains intact. Suggest and explain why the inner membrane of a mitochondrion remains intact when the organelle is placed in pure water. ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ..................................................................................................................................... [2] (ii) Name three molecules, other than coenzymes, that are found in the mitochondrial matrix and explain their role in aerobic respiration. ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ..................................................................................................................................... [3] (iii) The inner membrane contains a very high proportion of the molecule cardiolipin. Cardiolipin makes the membrane impermeable to some ions. Suggest why the inner membrane contains a very high proportion of cardiolipin. ........................................................................................................................................... ........................................................................................................................................... ..................................................................................................................................... [1] © UCLES 2022 9700/43/O/N/22 [Turn over PMT

Question